VCE+Notes+ for+Biology+Unit+2

 =VCAA outline of the unit= =Class notes for Unit 2= VCAA outline =Area of Study 1= Cell cycle Mitosis and Meiosis Stem cells Creating stem cells, Embryonic stem cells, Development of Zygote, Embryo and Foetus ASEXUAL REPRODUCTION Sexual Reproduction Cell differentiation and growth =Area Of study 2= Genomes HGP (ethics and legality) Determining size of genomes DNA Duplication DNA Transcription (bases and codons) Units of DNA Human Karyotypes Mendel's laws Chromosomes gene carriers, (locus, alleles and linkage) traits Genes editing (genetic sequencing) Punnett squares -monohybrid crosses and test crosses Crosses with co dominant genes polygenic inheritance Punnett squares dihybrid crosses and test crosses pedigrees and interpretting them (dominant, recessive, autosomal or sex linked) Sex linked diseases

Genetic screening epigenetics

 Unit 2: How is continuity of life maintained? In this unit students focus on asexual and sexual cell reproduction and the transmission of biological information from generation to generation. The role of stem cells in the differentiation, growth, repair and replacement of cells in humans is examined, and their potential use in medical therapies is considered. Students explain the inheritance of characteristics, analyse patterns of inheritance, interpret pedigree charts and predict outcomes of genetic crosses. They consider the role of genetic knowledge in decision-making about the inheritance of various genetic conditions. In this context the uses of genetic screening and its social and ethical issues are examined. A student investigation into, and communication of, an issue related to genetics and/or reproductive science is undertaken in Area of Study 3. The investigation draws on content from Area of Study 1 and/or Area of Study 2.

Area of Study 1 How does reproduction maintain the continuity of life? In this area of study students consider the need for the cells of multicellular organisms to multiply for growth, repair and replacement. They examine the main events of the cell cycle in prokaryotic and eukaryotic cells. Students become familiar with the key events in the phases of the cell cycle, and focus on the importance of the processes involved in a cell’s preparation for cell division. Students investigate and use visualisations and modelling to describe the characteristics of each of the phases in mitosis. Cytokinesis is explained for both plant and animal cells. Students describe the production of gametes in sexual reproduction through the key events in meiosis and explain the differences between asexual and sexual reproduction in terms of the genetic makeup of daughter cells. Students consider the role and nature of stem cells, their differentiation and the consequences for human prenatal development and their potential use to treat injury and disease.

Outcome 1 On completion of this unit the student should be able to compare the advantages and disadvantages of asexual and sexual reproduction, explain how changes within the cell cycle may have an impact on cellular or tissue system function and identify the role of stem cells in cell growth and cell differentiation and in medical therapies. To achieve this outcome the student will draw on key knowledge outlined in Area of Study 1 and the related key science skills on pages 10 and 11 of the study design.

=Key knowledge=

The cell cycle
• derivation of all cells from pre-existing cells through completion of the cell cycle • the rapid procession of prokaryotic cells through their cell cycle by binary fission • the key events in the phases (G1, S, G2, M and C) of the eukaryotic cell cycle, including the characteristics of the sub-phases of mitosis (prophase, metaphase, anaphase and telophase) and cytokinesis in plant and animal cells.

Asexual reproduction
• the types of asexual reproduction including fission, budding, vegetative propagation and spore formation • the biological advantages and disadvantages of asexual reproduction • emerging issues associated with cloning, including applications in agriculture and horticulture.

Sexual reproduction
• how an offspring from two parents has a unique genetic identity • the key events in meiosis that result in the production of gametes from somatic cells including the significance of crossing over of chromatids between homologous chromosomes in Prophase 1 and the non-dividing of the centromere in Metaphase 1 • the biological advantage of sexual reproduction, specifically the genetic diversity in offspring. Cell growth and cell differentiation • the types and function of stem cells in human development, including the distinction between embryonic and adult stem cells and their potential use in the development of medical therapies • the consequences of stem cell differentiation in human prenatal development including the development of germ layers, types of tissues formed from germ layers and the distinction between embryo and foetus • the disruption of the regulation of the cell cycle through genetic predisposition or the action of mutagens that gives rise to uncontrolled cell division including cancer and abnormal embryonic development.

Area of Study 2 How is inheritance explained? In this area of study students build on their understanding of the nature of genes and the use of genetic language to read and interpret patterns of inheritance and predict outcomes of genetic crosses. They gain an understanding that a characteristic or trait can be due solely to one gene and its alleles, or due to many genes acting together, or is the outcome of genes interacting with external environmental or epigenetic factors. Students apply their genetic knowledge to consider the social and ethical implications of genetic applications in society including genetic screening and decision making regarding the inheritance of autosomal and sex-linked conditions.

Outcome 2 On completion of this unit the student should be able to apply an understanding of genetics to describe patterns of inheritance, analyse pedigree charts, predict outcomes of genetic crosses and identify the implications of the uses of genetic screening and decision making related to inheritance. To achieve this outcome the student will draw on key knowledge outlined in Area of Study 2 and the related key science skills on pages 10 and 11 of the study design. =Key knowledge=

Genomes, genes and alleles
• the distinction between a genome, gene and allele • the genome as the sum total of an organism’s DNA measured in the number of base pairs contained in a haploid set of chromosomes • the role of genomic research since the Human Genome Project, with reference to the sequencing of the genes of many organisms, comparing relatedness between species, determining gene function and genomic applications for the early detection and diagnosis of human diseases.

Chromosomes
• the role of chromosomes as structures that package DNA, their variability in terms of size and the number of genes they carry in different organisms, the distinction between an autosome and a sex chromosome and the nature of a homologous pair of chromosomes (one maternal and one paternal) as carrying the same gene loci • presentation of an organism’s set of chromosomes as a karyotype that can be used to identify chromosome number abnormalities including Down’s, Klinefelter’s and Turner’s syndromes in humans.

Genotypes and phenotypes
• the use of symbols in the writing of the genotypes for the alleles present at a particular gene locus • the distinction between a dominant and recessive phenotype • the relative influences of genetic material, environmental factors and interactions of DNA with other molecules (epigenetic factors) on phenotypes • qualitative treatment of polygenic inheritance as contributing to continuous variation in a population, illustrated by the determination of human skin colour through the genes involved in melanin production or by variation in height.

Pedigree charts, genetic cross outcomes and genetic decision-making
• pedigree charts and patterns of inheritance including autosomal dominant, autosomal recessive, X-linked and Y-linked traits • the determination of genotypes and prediction of the outcomes of genetic crosses including monohybrid crosses, and monohybrid test crosses • the inheritance of two characteristics as either independent or linked, and the biological consequence of crossing over for linked genes • the nature and uses of genetic testing for screening of embryos and adults, and its social and ethical implications.

Area of Study 3 Investigation of an issue The increasing uses and applications of genetics knowledge and reproductive science in society both provide benefits for individuals and populations and raise social, economic, legal and ethical questions. Human cloning, genetic modification of organisms, the use of forensic DNA databanks, assisted reproductive technologies and prenatal and predictive genetic testing challenge social and ethical norms. In this area of study students apply and extend their knowledge and skills developed in Areas of Study 1 and/or 2 to investigate an issue involving reproduction and/or inheritance. They communicate the findings of their investigation and explain the biological concepts, identify different opinions, outline the legal, social and ethical implications for the individual and/or species and justify their conclusions. Material for the investigation can be gathered from laboratory work, computer simulations and modelling, literature searches, global databases and interviews with experts.

Outcome 3 On completion of this unit the student should be able to investigate and communicate a substantiated response to a question related to an issue in genetics and/or reproductive science. To achieve this outcome the student will draw on key knowledge outlined in Area of Study 3 and the related key science skills on pages 10 and 11 of the study design.

=Key knowledge=

Scientific method
• the characteristics of effective science communication: accuracy of biological information; clarity of explanation of biological concepts, ideas and models; contextual clarity with reference to importance and implications of findings; conciseness and coherence; and appropriateness for purpose and audience • the biological concepts specific to the investigation: definitions of key terms; use of appropriate biological terminology, conventions and representations • the use of data representations, models and theories in organising and explaining observed phenomena and biological concepts, and their limitations • the nature of evidence and information: distinction between opinion, anecdote and evidence, weak and strong evidence, and scientific and non-scientific ideas; and validity, reliability and authority of data including sources of possible errors or bias • the influence of social, economic, legal and ethical factors relevant to the selected biological issue.

Assessment The award of satisfactory completion for a unit is based on whether the student has demonstrated the set of outcomes specified for the unit. Teachers should use a variety of learning activities and assessment tasks that provide a range of opportunities for students to demonstrate the key knowledge and key skills in the outcomes.

The areas of study, including the key knowledge and key skills listed for the outcomes, should be used for course design and the development of learning activities and assessment tasks. Assessment must be a part of the regular teaching and learning program and should be completed mainly in class and within a limited timeframe. All assessments at Units 1 and 2 are school-based. Procedures for assessment of levels of achievement in Units 1 and 2 are a matter for school decision. For this unit students are required to demonstrate achievement of three outcomes. As a set these outcomes encompass all areas of study. Suitable tasks for assessment may be selected from the following:

For Outcomes 1 and 2 • a report of a fieldwork activity • annotations of a practical work folio of activities or investigations • a bioinformatics exercise • media response • data analysis • problem solving involving biological concepts, skills and/or issues • a reflective learning journal/blog related to selected activities or in response to an issue • a test comprising multiple choice and/or short answer and/or extended response.

For Outcome 3 • a report of an investigation into genetics and/or reproductive science using an appropriate format, for example, digital presentation, oral communication or written report. Where teachers allow students to choose between tasks they must ensure that the tasks they set are of comparable scope and demand. Practical work is a central component of learning and assessment. As a guide, between 3½ and 5 hours of class time should be devoted to student practical work and investigations for each of Areas of Study 1 and 2. For Area of Study 3, between 6 and 8 hours of class time should be devoted to undertaking the investigation and communicating findings.

The cell is a dynamic system of interacting molecules that define life. An understanding of the workings of the cell enables an appreciation of both the capabilities and the limitations of living organisms whether animal, plant, fungus or microorganism. The convergence of cytology, genetics and biochemistry makes cell biology one of the most rapidly evolving disciplines in contemporary biology. In this unit students investigate the workings of the cell from several perspectives. They explore the importance of the insolubility of the plasma membrane in water and its differential permeability to specific solutes in defining the cell, its internal spaces and the control of the movement of molecules and ions in and out of such spaces. Students consider base pairing specificity, the binding of enzymes and substrates, the response of receptors to signalling molecules and reactions between antigens and antibodies to highlight the importance of molecular interactions based on the complementary nature of specific molecules. Students study the synthesis, structure and function of nucleic acids and proteins as key molecules in cellular processes. They explore the chemistry of cells by examining the nature of biochemical pathways, their components and energy transformations.

Cells communicate with each other using a variety of signalling molecules. Students consider the types of signals, the transduction of information within the cell and cellular responses. At this molecular level students study the human immune system and the interactions between its components to provide immunity to a specific antigen. A student practical investigation related to cellular processes and/or biological change and continuity over time is undertaken in either Unit 3 or Unit 4, or across both Units 3 and 4, and is assessed in Unit 4, Outcome 3. The findings of the investigation are presented in a scientific poster format as outlined in the template on page 12.

Area of Study 1 How do cellular processes work? In this area of study students focus on the cell as a complex chemical system. They examine the chemical nature of the plasma membrane to compare how hydrophilic and hydrophobic substances move across it. They model the formation of DNA and proteins from their respective subunits. The expression of the information encoded in a sequence of DNA to form a protein is explored and the nature of the genetic code outlined. Students use the lac operon to explain prokaryotic gene regulation in terms of the ‘switching on’ and ‘switching off’ of genes. Students learn why the chemistry of the cell usually takes place at relatively low, and within a narrow range of, temperatures. They examine how reactions, including photosynthesis and cellular respiration, are made up of many steps that are controlled by enzymes and assisted by coenzymes. Students explain the mode of action of enzymes and the role of coenzymes in the reactions of the cell and investigate the factors that affect the rate of cellular reactions. Outcome 1 On completion of this unit the student should be able to explain the dynamic nature of the cell in terms of key cellular processes including regulation, photosynthesis and cellular respiration, and analyse factors that affect the rate of biochemical reactions. To achieve this outcome the student will draw on key knowledge outlined in Area of Study 1 and the related key science skills on pages 10 and 11 of the study design. Unit 3: How do cells maintain life? VCE Study Bi

=Class notes= Area of Study 1

The Cell cycle
The cell cycle of a eukaryote has 4 distinct phases The M phase - Mitosis - which requires the nuclear material to be doubled and to be divided. This is followed by cytokinesis a check point that requlates the progression to the next phase. The cell spends 90% of its time in interphase. This can further be divided into 3 phases G1 gap phase for growth and development of the cell S phase Chromosome replication - DNA synthesis so there is now enough genetic material to make 2 sets of chromomsoes G2 the second gap phase rapid cell growth and protein synthesis. The cell is preparing for mitosis.

Check points
**G1 checkpoint** occurs at the G1 (Gap 1) stage of interphase. The cell is ready to undergo division so a check of the DNA of the cell occurs. If the DNA is found to be damaged or incomplete the cell is stopped from continuing through the cell cycle. Instead, the cell may enter a non-dividing quiescent stage called G0, or it may be targeted for destruction. ( the ‘security guard’ at the G1 checkpoint is a protein known as p53, a tumour-suppressor protein.) G2 checkpoint ensures all the genetic material is correct (complete and no damage)- ready to go to mitosis stage The **M checkpoint - sometimes called the spindle assembly stage - this occurs in the metaphase stage of mitosis. The check ensures that the spindle fibres is attached to the correct sister chromosome. - if an error is identified the mitotic division is stopped.**



 =mitosis -phases= Watch this animation to show you all the phases of mitosis and how the chromosomes line up and pull apart. Genetics Parts of the nucleus - inside the nucleus is the genetic material. DNA is the chemical name for the double helix structure Gene - this is a section of the long DNA strand - Genes are found on the chromosomes. CHromosome made of chromatin - loose masses of DNA and associated proteins centromere -the join - where the sister chromosomes touch. Chromatids - two chromatids make up one chromosome

the role of the centriole (only found in animal cells) spindle fibres mitosis -phases another link to the same animation - note the section called cytokinesis cytokinesis - this is show clearly in the animation Happens after telophase - In general the cytosol collects around each nuclei and the organelles surround each of the nuclei - dividing equally (depending on where they were in the cytosol) cytokinesis in animal cells - a cleavage furrow forms in the cell after telophase, Centrioles replicate, Cytokinesis in plant cells - a cell plate forms after telophase (no centrioles) dividing the cell and then the new cell wall forms.
 * Note the key differences in cytokinesis between plants and animal cells**

When two new nuclei are formed each needs to be combined with cytosol to give two new cells. Obviously the **organelles such as mitochondria and chloroplasts within the cytosol must also be replicated during the cell cycle,** otherwise cells would contain an ever-decreasing number of these structures.

Mitochondria and chloroplasts contain DNA must replicate before the organelles divide -

Mitochondria have their own DNA called - mitochondrial DNA - Direct inheritance from the maternal line - due to only the ovum containing mitochondria ( the sperms mitochondria is left at the outside of the ovum at fertilisation). Anthropologists have studied the maternal mitochondrial DNA and have used this to trace backward where our mothers have come from. THey have proposed the original mother (Eve) appeared iin Central Africa about 200,000 years ago. Although recent discoveries published in May 2017 have found human bones near Morocco and these bones are being classified as modern humans and dated at 300,000 years old. This brings into questions whether humans really did radiated out from one area in Africa or started to appear concurrently and interbred to form our species.

Evolution and mtDNA (or mitochondrial DNA) more on mitochondrial DNA

=**Stem cells**= **Haematopoietic stem cells**, located in the bone marrow, divide to give rise to cells that subsequently differentiate into the various types of blood cells, including red blood cells, white blood cells of various kinds and platelets.
 * epidermis** - skin cells, about 2 months
 * epithelial cells** - intestine wall - 4 to 5 days

__//**more on Stem cells and how it links to differentiation**//__

Diseases and mitosis excess/ uncontrolled mitosis results in an overgrowth of cells. They continue to divide without differnetiating. In other words the checkpoint of G1 and the tumor suppressor protein p53 does not function.

Epicormic shoots after teh bushfire Reproduction in Fungi reproduction in liverworts and ferns

ASEXUAL REPRODUCTION - Chap 10 Examples of asexual reproduction in which a single parent produces identical o spring include:
 * binary fission in prokaryotic microbes - bacteria
 * splitting in single-celled eukaryotic organisms -amoeba, paramecium
 * spore formation in fungi
 * natural cloning in animals, for example
 * – budding in sponges and corals, eg hydra division of flatworms- nematodes
 * – ‘virgin birth’ in insects - parthenogenesis in invertabrates - common but also found in some lizards - only females exist

suckers.
 * vegetative reproduction in plants, as in runners, cuttings, rhizomes and

http://www.pbslearningmedia.org/resource/biot09.sci.life.gen.cloning/animal-cloning-101/ http://learn.genetics.utah.edu/content/cloning/clickandclone/
 * Cloning - plants, animals **
 * Watch a simple example of cloning and the various types**
 * play the cloning game**

Sexual Reproduction Meiosis gametes and production and fertilization video of meiosis.

https://www.youtube.com/watch?v=BmSTdA3wIs0

haploid, diploid, phases, reduction division, as a source of variability

crossing over, recombinations The sister chromatids are no longer identical. This creates genetic variation because when they separate into the gametes there is no identical chromosomes. Where the sister chromatids touch in the crossing over process is called the chiasmata. Misregulation of chromosomes in meiosis showing nondisjunction leading to trisomy x and others http://www.sciencebook.dkonline.com/59.html

Advantages, disadvantages

External vs internal fertilisation advantages and disadvantages The need for water - (liquid) If fertilisation occurs on water then millions of gametes are released. to increase the chances of meeting another suitable gamete- eg. coral spawning The simpler the animal the more likely fertilisation will happen in water- from porifera, to amphiibians ( porfifera, cnidarians, echinodermata, annelida, fish- exceptions --some land snails- these are hermaphrodites - containing both male and female gametes and genitalia or genitalia that can be interchanged.

Internal fertilisation increase chances of fertilisation. No parental care provided means more eggs need to be laid. If there is parental care - eg birds in a nest - then less eggs are laid. With mammals - increased parental care means limited number of offspring. some species produce an egg - the structure of the egg

MAcropod reproduction in marsupials http://kangaroocreekfarm.com/about-roos/

chromosome replication media type="custom" key="28652895"

Chapter 12 Antenatal human development Ovulation, Copulation (sperm viable upto 48 to 72 hours) Fertilisation and the formation of zygote: First mitotic division forms the Embryo days 1 to 5 - mitosis= fairly solid mass of cells after first 5 days - mitosis results in the formation of a fluid filled sac of cells = Blastocyst - inner cell mass forms the tissues of the embryo while the outer cell mass forms the placenta. days 6 onward; gastrulation - the migration of cells to form tissues three main types these primary germ layers are formed of stem cells that differentiate into tissues Up to day 63 (about the first 9 weeks - these layers start to form tissues that combine to form organs eg Ectoderm; skin, melanocytes, brain (CNS and PNS) pituitary gland, adrenal medulla, sense organs - eyes, inner ears eg Mesoderm; heat and blood vessels, adrenal cortex, muscle-smooth,skeletal and cardiac, part of urogenital, bone marrow, blood, cells lymphatic, bone and cartilage eg Endoderm; larynx, trachea, lungs, linings of; respiratory & gastrointestinal tract,liver, pancreas, thymus, thyroid, bladder, urethra.
 * Cell differentiation and growth**
 * stages of the embryo**
 * 1. ectoderm
 * 2. mesoderm,
 * 3. endoderm

chemicals like teratogens eg. thalidomide affects formationof organs - if taken within the embryonic stage week 3 to 9.
 * Things that cause problems**

see text book figure 12.8 for more details,

Foetus stage - from week 10 to birth (week 38)

Stem cells are undifferentiated cells found in multicellular organisms. They are characterised by the properties of self renewal and potency self renewal means they undergo mitosis to produce more of their kin potency refers to the umber of types of differentiation they can under go Totipotent - differentiate into any cell in the embryo Pluripotent - differentiate only into embryo cells - not placenta or chorion Multipotent - differentiate into cells of one organ system. Oligopotent - can differentiate into a few cells like somatic lymphoid and myloid stem cells Unipotent - can produce cells of their own type - but because they can renew they are called stem cells eg muscle cells
 * Key events and stem cells**

Once a cell is differentiated we say it is specialised and can not be undifferentiated. Sources of stem cells Embyonic stem cells (ESC) - obtained from the inner mass of the blastocyst - coming from excess embryos developed from IVF - Is it ethical? Parthenotes - taken from unfertilised eggs that are artificially stimulated to start development Adult stem cells - somatic stem cells - bone marrow, skin, liver, brain, adipose tissue, blood, -- umbilical cord blood or the cord itself after birth. - these are multipotent - give rise to mmore skin cells or more blood cells Indused pluripotent stems cells

=__//**more on Stem cells**//__= do the task on __//**education perfect**//__ and take some notes there www.educationperfect.com/app/#/dashboard/homework/264540

https://www.theguardian.com/teacher-network/2015/sep/07/six-creative-ways-teach-genetics-genes __//**USe the site below to find out how stem cells (niche stem cells) can be used to replace blood cells and more**//__ http://learn.genetics.utah.edu/content/stemcells/sctypes/ media type="custom" key="28663212"

the stem cell board game http://www.embl.it/training/scienceforschools/teacher_training/teachingbase/stem_cell_engl/index.html

Ethics and stem cells -- http://www.eurostemcell.org/conversations-ethics-science-stem-cells Therapeutic Stem cells -- iPS - http://www.eurostemcell.org/stem-cells-future-introduction-ips-cells Tumor formation -- http://www.eurostemcell.org/media-and-resource-library?keywords=&type[96]=96
 * Some videos to watch**

http://www.eurostemcell.org/media-and-resource-library?keywords=&type[96]=96
 * More videos**

 =Area Of study 2= useful links http://www.yourgenome.org/facts/what-is-dna-replication Genomes HGP = human genome project - map all the genes in the human chromosomes ( karyotype). Started in 1990 and completed in 2003. Current technologies can provide a persons genome. Originally it took 10 years. Number.

How the Human Genome was sequenced.

Genes average about 3000 nucleotides in length, but considerable variation about that average exists SHould you be able to know your genome should insurance companies know your genome should an employer know your genome bioethicist Genetic sequences These indicate position of bases and hence the position of genes.. Knowing a sequence can tell you 1. how closeley related a species is, 2. what proteins/ enzymes / detox pathways/ an individual can or can not make and hence what diseases you may or may not get. 3. possible treatments for disease. 4. can determine the size of a genome more about genetic sequences (linkage etc)
 * (ethics and legality)**

Genome size is usually measured in base pairs (or bases in single-stranded DNA or RNA). The C-value is another measure of genome size. The C-value refers to the amount, in picograms, of DNA contained within a haploid nucleus (e.g. a gamete) or one half the amount in a diploid [|somatic][| cell]  of a [|eukaryotic]  organism. In some cases (notably among diploid organisms), the terms C-value and genome size are used interchangeably, however in polyploids the C-value may represent two or more genomes contained within the same nucleus. ( total haploid genome content of 3 pg (3 picograms), which translates into a molecular weight of 1.8 x 10 12 daltons (Da).)
 * Determining size of genomes**

The smallest unit of genetic information is the basepair (bp) which has a molecular weight of ~600 Da. By dividing this number into the total haploid DNA mass, one arrives at an approximate value for the total information content in the haploid genome: three billion bp, which can also be written as three million kilobasepairs (kb) or 3,000 megabasepairs (mb). All eutherian mammals have genomes of essentially the same size

Source: Boundless. “Variations in Size and Number of Genes.” Boundless Biology . Boundless, 26 May. 2016. Retrieved 13 Sep. 2016 from __https://www.boundless.com/biology/textbooks/boundless-biology-textbook/evolution-and-the-origin-of-species-18/evolution-of-genomes-127/variations-in-size-and-number-of-genes-513-13093/__

= Genome Sizes = The genome of an organism is the complete set of genes specifying how its phenotype will develop (under a certain set of environmental conditions). In this sense, then, **diploid** organisms (like ourselves) contain two genomes, one inherited from our mother, the other from our father. The table below presents a selection of representative genome sizes from the rapidly-growing list of organisms whose genomes have been sequenced. //__**How is sequencing done**__// go here for a fascinating video https://www.yourgenome.org/video/dna-sequencing

Karyotype - the full set of chromosomes arranged in homologous chromosome pairs.

http://www.yourgenome.org/facts/what-is-a-chromosome-disorder

WHat does knowing the genome tell you?
Comparing relatedness of species. Scientists can compare the gene sequence responsible for the production of a protein and identify where it is on a chromosome (ie they compare the genes locus). Differences between species in the locus of this protein indicates the number of random mutations that have occurred in each species ( from the time of the common ancestor until now.) Species who have diverged recently have more similarities in their DNA sequencing of the gene being studied than those that have diverged long ago. One such eg is the gene for cytochtome c responsible for the formation of a protein used in cellular respiration. By comparing the position of the gene on the chromosome in different species tells you how closely they are related- because over time evolution will have introduced mutations to the gene and the order of bases. Species with a base pattern very similar to each other are very closely related.

Sequencing can be used in determining disease outbreaks when examining the DNA sequence in viruses or bacteria. (changed / mutations ) are more likely to bring about an outbreak of disease.

Knowing the entire genome does tell you what each gene does.

detection of diseases- Early detection can lead to better results and health outcomes. It can be used to control epigenetic influences and hence not cause the gene to express a trait.

Forensic sciences - individuals (while having similar pattern to other memnbers of their species ) it is not exacgt - otherwise they would be an identical twin - or clone. Therefore forensic DNA analysis can determine the DNA of an individual

Ethical Legal and Social issues Storing the data of the genome has been enhanced by computer development - eg databases can store the info and allow quick retrival and comparison of data. This can be used to compare the genomes of individuals and find differences. Overtime it is thought many individuals will have their genome sequenced. It will require privacy laws to be maitined to protect some indiviuals EG insurance ( ife and or Health) companies may not insure individuals, Some private companies may try to develop health solutions based on a persons genes and sell this to only the wealthy.

Ethical, Legal and Social Issues in Genomic Medicine
Genomics is the study of an organism's whole hereditary information that is present in its genes (DNA) and the use of its genes. It deals with the use of genome information associated with other information to provide answers in biology and medicine. Genomic research may greatly change the practice of health care. But genomic research alone is not enough to apply this new knowledge to improving human health. We need to carefully study the many ethical, legal and social issues raised by this research. Such study is crucial to being able to use genomic research to help patients and to preventing misuse of new genetic technologies and information. Ethical, legal and social issues raised by genomic research include: Controversial issues such as cloning, stem cell research and eugenics also need to be carefully studied. get more from
 * Possible discrimination by employers or health insurers
 * <span style="background-color: #ffffff; color: #333333; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 14px;">The need for ethical standards for work with human research subjects or tissues
 * <span style="background-color: #ffffff; color: #333333; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 14px;">Consideration of social, cultural and religious perspectives on genetics and health

Fillin the blanks sheet for this section Answer sheet

The result would be

If all this is available

DNA Duplication or DNA replication (means the same) a video of how DNA replication happens a video on how DNA was discovered by The man who discovered it Happens in the process of Mitosis (prophase) and the process of Meiosis (prophase 1 also get crossing over at this point). DNA is Deoxyribose Nucleic Acid The structure of DNA 1. The components and structure of DNA are a. the nucleotides- have 3 parts a) the sugar (deoxyribose), b) The phosphate, c) the nitrogen containing base b. bases (C, G and A, T) The Cytosine matches up to the Guanine while the Adenine matches up to the Thymine. c) one example of a nucleotide is andenosine monophosphate this is the base adnosine joined with the sugar and phosphate. d. they are arranged in a double helix wrapped around a histone e) types of chromosomes - sex chromosomes and autosomes ( all the others - sometimes called body chromosomes or somatic chromosomes) IN humans their are 22 pairs of autosomes and 2 sex chromosomes -

Here is a movie http://www.yourgenome.org/video/dna-replication

How it works step 1 - the parent DNA unzips at one end. Step 2 - Copying of the DNA has begun, with COMPLIMENTARY bases attaching to BOTH strands of the DNA Step 3 - Replication results in two identical strands of DNA.

Extension the video talks about 3 prime and 5 prime here is a short explanation of each The 5' and 3' mean "five prime" and "three prime", which indicate the carbon numbers in the DNA's sugar backbone. The 5' carbon has a phosphate group attached to it and the 3' carbon a hydroxyl group. This asymmetry gives a DNA strand a "direction". For example, DNA polymerase works in a 5' -> 3' direction, that is, it adds nucleotides to the 3' end of the molecule (the -OH group), thus advancing to that direction.

DNA Transcription This is used as part of the protein synthesis process. Main things to remember is that the base Thymine is replaced by Uracil so the process is step 1 The parent DNA unzips at one part of the double helix step 2 mRNA is formed as part of the transcription process (an eg of a strand of messenger RNA is UUAAGCA it would have coded to a piece of DNA that would have the base order AATTCGT) Step 3 the mRNA leaves the nucleus and sits on the ribosomes. Every set of 3 bases is called a codon and they code on to an amino acid. The special order of amin0 acids gives you a specific protein, <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px;">While the specific nucleotide sequence of an mRNA specifies which amino acids are incorporated into the protein product of the gene from which the mRNA is transcribed, the **<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px;">role of tRNA **<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px;"> is to specify which sequence from the genetic code corresponds to which amino acid. <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px; line-height: 0px; overflow: hidden;"> Watch this http://www.yourgenome.org/video/from-dna-to-protein

Genes and Alleles A gene is the section of DNA containing an sequence of bases that are responsible for coding a particular protein. An allele is the pair of genes. Remember one gene is on the chromosome while its pair or allele is on same location of the homologous chromosome. (Homologous pairs of chromosomes contain the alleles)

Human Some background on karyotypes <span style="font-family: Arial,Helvetica,sans-serif;">Sometimes during the processes of meiosis and the creation of gametes and zygotes, errors are made and individuals are born with additional or missing chromosomes. The word Trisomy in a disorders name indicates that there are three copies of a particular chromosome instead of two. <span style="font-family: Arial,Helvetica,sans-serif;">Trisomy 18 (Edwards) <span style="font-family: Arial,Helvetica,sans-serif;">Trisomy 13 (Patau) <span style="font-family: Arial,Helvetica,sans-serif;">47,XXY (Kleinfelters) <span style="font-family: Arial,Helvetica,sans-serif;">47,XYY <span style="font-family: Arial,Helvetica,sans-serif;">47,XXX <span style="font-family: Arial,Helvetica,sans-serif;">45,X || <span style="font-family: Arial,Helvetica,sans-serif;">1 in 700 <span style="font-family: Arial,Helvetica,sans-serif;">1 in 3000 <span style="font-family: Arial,Helvetica,sans-serif;">1 in 5000 <span style="font-family: Arial,Helvetica,sans-serif;">1 in 1000 males <span style="font-family: Arial,Helvetica,sans-serif;">1 in 1000 males <span style="font-family: Arial,Helvetica,sans-serif;">1 in 1000 females <span style="font-family: Arial,Helvetica,sans-serif;">1 in 5000 females ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">Probability of Being Born With Specific Chromosomal Disorders ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">Trisomy 21 (Down)

<span style="font-family: Arial,Helvetica,sans-serif;">The most common chromosomal disorder is Trisomy 21, more commonly known as Down Syndrome. Symptoms of Trisomy 21 include individuals with a broad, flat face, a thick tongue and a small nose and mild to moderate mental retardation.

<span style="font-family: Arial,Helvetica,sans-serif;">Trisomy 18 is also known as Edwards Syndrome and affects girls almost 3 times as often as boys. Symptoms include: low birth weight, mental retardation, low-set or malformed ears, small jaw, hand abnormalities, congenital heart disease, hernias, and undescended testicles. 50% of those born with Trisomy 18 often don’t live past the first few months of life.

<span style="font-family: Arial,Helvetica,sans-serif;">Trisomy 13 is also called Patau syndrome. Symptoms include: small eyes with defects in the iris, cleft lip, cleft palate, and low-set ears. Congenital heart disease is present in approximately 80% of affected infants. Hernias and genital abnormalities are common. 80% of infants born with Trisomy 13 don’t survive the first month while survivors have severe mental defects. Rarely does a child inflicted with Trisomy 13 survive to adulthood.

<span style="font-family: Arial,Helvetica,sans-serif;">XXY Syndrome is also referred to a Kleinfelters Syndrome. This disorder affects only boys. Symptoms include: development of breasts, spare facial hair, and an inability to produce sperm.

<span style="font-family: Arial,Helvetica,sans-serif;">XYY Syndrome affects only boys. There are no noticeable physical differences with this disorder. Symptoms include: increased activity, delayed mental maturity, and in creased tendency for learning problems in school.

<span style="font-family: Arial,Helvetica,sans-serif;">XXX Syndrome is known as Triple or Triplo X. This disorder affects only females. Again, there are no physical indications of Triplo X. Symptoms include: possible delayed menopause, and increased probability of delayed development in motor function, speech, and maturation

<span style="font-family: Arial,Helvetica,sans-serif;">XO Syndrome is more commonly known as Turner Syndrome and affects only girls. There are minimal physical abnormalities and Turner’s does not affect intellect. The primary effect of Turner’s is due to the missing X chromosome. This causes infertility.

<span style="font-family: Arial,Helvetica,sans-serif;">**Related and Resource Websites**

<span style="font-family: Arial,Helvetica,sans-serif;">[]

<span style="font-family: Arial,Helvetica,sans-serif;">[|http://oak.cats.ohiou.edu/~schutte/new_page_1.htm]

<span style="font-family: Arial,Helvetica,sans-serif;">[|http://www.genetics.org]

<span style="font-family: Arial,Helvetica,sans-serif;">[]

=Mendel's Laws= <span style="color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px; vertical-align: baseline;">1. Law of segregation <span style="color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px; vertical-align: baseline;">Definition: <span style="background-color: #ffffff; color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px;">The principles that govern heredity were discovered by a monk named Gregor Mendel in the 1860's. One of these principles, now called <span style="color: #0099cc; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px; vertical-align: baseline;">[|Mendel's law of segregation] <span style="background-color: #ffffff; color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px;">, states that <span style="color: #0099cc; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px; vertical-align: baseline;">[|allele] <span style="background-color: #ffffff; color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px;"> pairs separate or segregate during <span style="color: #0099cc; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px; vertical-align: baseline;">[|gamete] <span style="background-color: #ffffff; color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px;"> formation, and randomly unite at <span style="color: #0099cc; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px; vertical-align: baseline;">[|fertilization] <span style="background-color: #ffffff; color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px;">. <span style="background-color: #ffffff; color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px;">2. Law of independent assortment <span style="background-color: #ffffff; color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px;">Alleles of one gene controlling one trait assort independently of another gene controlling a different trait.

<span style="background-color: #ffffff; color: #191919; font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 16px;">Repercussion of law 2-If they do not sort independently the genes may be linked - ie reside on the same chromosome

Determining DNA Sequences Chromosomes gene carriers ( locus, alleles and linkage) traits) A trait is the characteristic that is evident by the gene. Eg the gene for flower colour produces plants with a flower colour dependent on the types of genes present. A string of genes are located on the same chromosome. These genes are called linkage groups. So following the presence of one gene as in the phenotype flower position will also show the presence of other genes in the linkage group. The history behind this is that Bateson and Punnett observed that some of Mendel's factors did not behave independently when moving into gametes. Therefore the these factors were not free floating. Sutton recognised the chromosomes inside the nucleus carried the factors. He based this on the following observations 1. alleles of genes segregate into different gametes and chromosomal pairs separate into different gametes (disjunction) 2. random assortment of alleles into different gametes and random assortment of members of the homologous pairs across the equator during meiosis

Morgan in 1910 demonstrated the existence of a specific gene on a particular position of a specific chromosome. This explained the close associate observed by Punnett and Bateson of the genes controlling pea flower colour was located on the same chromosome as genes controlling pea flower shape (hooded and erect).

Chromosomes and sex determination -Mammals - XX / XY Birds and some reptiles Females WZ males ZZ Incubation temperature and sex determination- eg Green turtles- Males if incubation > 31deg C, females at < 27 deg C but equal numbers male and female at about 29 degC Gene editing watch the catalyst program for the latest on gene editing http://www.abc.net.au/catalyst/stories/4529197.htm

<span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> Other factors that lead to more genetic variation and happen during meiosis are: __*Crossing over__: homologous chromosomes literally "cross over" each other--When they get ready to divide, and chromosomes are pulled apart, pieces of each homologous chromosome get switched. (See Prophase I in the Meiosis image above.) *__Independent Assortment__: when the chromosomes separate, they do so at random--all gametes should get an allele for each trait, but there's no certain combination that has to occur. <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> =**Punnett squares -monohybrid crosses**=

<span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">**You should be able to predict offspring ratios on a variety of inheritance patterns (including dominance, co-dominance, incomplete dominance, multiple alleles, and sex-linked traits.** <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">eg <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">
 * Traits ** (or observable characteristics) are determined by the ** alleles ** received from each parent. Remember, alleles are different versions of the same trait. So the trait for freckles has two alleles: the allele for freckles (F) and the allele for no freckles (f). Alleles can be dominant (represented by capital letter) or recessive (lower case letter). Dominant alleles express themselves more then recessive alleles do. In a normal ** genotype **(letter code representing the alleles), you could have FF ( homozygous dominant), Ff ( heterozygous dominant), or ff (recessive). In this example, only one dominant allele is necessary for that allele to be expressed in the trait. For the recessive alleles to be expressed, both alleles inherited must be recessive. The ** phenotype ** (appearance of the trait--what it looks like) for FF or Ff is freckles. The phenotype for ff is no freckles. <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">
 * Directions: **// Answer each of the following questions using a Punnett Square and the rules of monohybrid crosses. //

1.) The allele for dimples (D) is dominant to the allele for no dimples (d). A man heterozygous for dimples marries a woman who is also heterozygous for dimples.

a.) What is the man’s genotype and the woman’s genotype?

b.) What is the man’s phenotype and the woman’s phenotype?

c.) Do a cross to determine all potential dimple genotypes and phenotypes for the offspring of this man and woman.

Working and Answers hetreozygus means a big letter and a little letter ( or more scientifically a dominant gene and a recessive gene) a) Dd for the female and Dd for the male

Because D is dominant and it stands for dimples b) both male and female will have a phenotype of dimples

Set up a punnett square like this female || D || d || c) the potential phenotype of the children would be 75% dimples : 25% no dimples <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">Monohybrid test crosses <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">cross a know homozygus recessive with a nother genotype and you can predict the genotype of The unknown genotype <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">eg <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">Yy X yy will give some plants with the recessive trait yy hence you know the other plant ahs a genotype of Yy <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">YY X yy will give no plants with the recessive trait hence you know the other plant had a genotype of YY <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> A monohybrid test cross is a special kind of cross in which an organism of uncertain genotype (T − ) is crossed with a homozygous recessive organism (tt).
 * male
 * D || DD || Dd ||
 * d || Dd || dd ||



<span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> <span style="background-color: #ffffff; color: #222222; display: block; font-family: arial,sans-serif; font-size: small;"> <span class="_Tgc" style="font-size: 16px;">For a **monohybrid cross** of two true-breeding parents, each parent contributes one type of allele resulting in all of the offspring with the same genotype. A **test cross** is a way to determine whether an organism that expressed a dominant trait was a heterozygote or a homozygote.

=== [|The Punnett Square Approach for a Monohybrid Cross - Boundless] this links to some diagrams to help explain this. === <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">Dihybrid Croses <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">This is when 2 genes are examined in the cross. They are genes that are on different chromosomes therefore they will assort randomly. Hence there are four possible combination of genes in the formation of a gamete. Eg in the case of parent with the heterozygus combination of PpQq the gametes that might form are <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">PQ, Pq, pQ, pq

<span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> Dihybrid crosses Test crosses one parent is a homozygus recessive the other is a heterozygus. Eg //ppqq X PpQq// Dihybrid test crosses were used to identify linkage relationship between 2 genes. For example if these 2 genes were on separate chromosomes (ie unlinked0 the will sort independently. See fig 16.26 for a n example cross. A dihybrid test cross can show whether or not 2 genes are assorting independently - if unlinked the cross will yield a 1:1:1:1 ratio of the four possible genotypes

Linked genes are those genes that are on the same chromosome. Hence <span style="background-color: #ffffff; color: #888888; display: block; font-family: Lato,sans-serif; font-size: 16px; text-align: center;">

[|Practice Problems!]

<span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">All genetics problems don't behave in the "normal" way. We call the exceptions "NonMendelian Genetics". These problems include: +**Incomplete Dominance** (the dominant allele isn't as able to mask the recessive allele): the heterozygous phenotype is a blend of the dominant and recessive (Ex: Red (RR) x White (rr) roses = Pink (Rr) roses) +**Codominance** (there is more than one dominant allele): (Ex: Blood type AB--both A and B are dominant, so both of their characteristics show up in the blood cells). See example in text book page 579 +**Multiple Alleles** (more than 2 alleles exist for a certain trait): Also seen in blood types where there are alleles for A, B, and O.) +**Sex-linked Traits** (the alleles are attached to the X-chromosome of the sex chromosomes) All of these problems depend on the gender/sex of the organisms. __Remember, the MALES are more likely to suffer from a sex-linked disorder because they only have one X!!!__ +**Polygenic Traits** (more than one gene controls a certain trait): Hair color, skin color, and height are controlled by more than one gene. Therefore genotypes could look like AaBBCcDDEe instead of with just one letter Aa. In skin color, the more dominant alleles obtained = darker skin color...the fewer dominant alleles obtained = lighter skin color. With polygenic traits, usually there are more members of the population with a blend of the dark and light and fewer members of the populations with the extreme (very dark/very light) phenotypes. <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">Pedigrees <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">We can observe how traits move through a family using **pedigrees** (family trees). Squares represent men, circles represent women. Shaded squares and circles HAVE the trait, unshaded squares and circles do not. Parents are connected with lines and their offspring appear below them. <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;">recessive pedigrees <span style="background-color: #ffffff; color: #2a2a2a; display: block; font-family: Lato,sans-serif; font-size: 16px;"> Haemaphilia and the royal family pedigree Examples using pedigrees PI - Pedigree investigator http://learn.genetics.utah.edu/content/addiction/pi/ use with worksheet

Queen Victorias Pedigree and Haemaphilia facts about haemaphilia 1.<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px; line-height: 1.5;"> is caused by a mutation in one of the genes, that provides instructions for making the clotting factor proteins needed to form a blood clot. This change or mutation can prevent the clotting protein from working properly or to be missing altogether. <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px; line-height: 1.5;">2. These genes are located on the X chromosome <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px; line-height: 1.5;">3. <span style="background-color: #ffffff; color: #545454; font-family: arial,sans-serif; font-size: small; line-height: 1.5;"> males can have <span style="background-color: #ffffff; color: #6a6a6a; font-family: arial,sans-serif; font-size: small; line-height: 1.5;">hemophilia <span style="background-color: #ffffff; color: #545454; font-family: arial,sans-serif; font-size: small; line-height: 1.5;"> if they inherit an affected X chromosome that has a mutation in either the factor VIII or factor IX gene <span style="background-color: #ffffff; color: #545454; font-family: arial,sans-serif; font-size: small; line-height: 1.5;">4. A <span style="background-color: #ffffff; color: #6a6a6a; font-family: arial,sans-serif; font-size: small; line-height: 1.5;">female <span style="background-color: #ffffff; color: #545454; font-family: arial,sans-serif; font-size: small; line-height: 1.5;"> with one affected X chromosome is a "carrier" of <span style="background-color: #ffffff; color: #6a6a6a; font-family: arial,sans-serif; font-size: small; line-height: 1.5;">hemophilia <span style="background-color: #ffffff; color: #545454; font-family: arial,sans-serif; font-size: small; line-height: 1.5;">.

Link to an example pedigeree of the royal family Exercise https://christophersonbiology.wikispaces.com/file/view/Pedigrees%20and%20Royal%20Family%20.pdf/487612496/Pedigrees%20and%20Royal%20Family%20.pdf

A detailed explanation of how the gene has mutated http://www.biology-pages.info/Q/Queen_Victoria.html

More on gene linkage 1. some genes are very close to each other on a chromosome. If they are less than 40 map units apart they are most likely going to be linked and not subject to crossing over ( but that crossing over might still happen) 2. where a gene is on its chromosome is called its Loci

so when meiosis is about to happen we can get eggs that are called **parental** **eggs** ( or noncrossover eggs ie the genes have not been separated by crossing over) and because they are identical the pattern of genes as the parent. But when crossing over occurs we call it recombinant eggs or crossing over eggs. See fig 16.27 fig 16.28 fig 16.29 fig 16.30 and fig 16.31

Detecting linkage if 2 gene loci are linked the outcome of a test cross can reveal that linkage. There will still be 4 classes of gametes but there will be many more of the parental gametes than the recombinant gametes. and hence a lot more of the offspring will have the parental traits of those 2 genes and not many offspring will have the recombinant genotype and hence phenotype.

Estimating the distance between linked genes Distance between Loci = (100 x the number of recombinant offspring) / total number of offspring see fig 16.33

Recombinant Genes

Epigenetics what is epigenteics https://ed.ted.com/lessons/how-the-choices-you-make-can-affect-your-genes-carlos-guerrero-bosagna https://www.ted.com/talks/moshe_szyf_how_early_life_experience_is_written_into_dna code

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