Compendium Review Genetics Part 2

8/14/2019 Compendium Review Genetics Part 2

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Compendium ReviewCompendium ReviewMajor Topic Two: GeneticsMajor Topic Two: Genetics

Table of ContentsTable of Contents

Part 3Part 3 Genotype and PhenotypeGenotype and Phenotype

Trait InheritanceTrait Inheritance

Beyond Inheritance PatternsBeyond Inheritance Patterns Sex-linked InheritanceSex-linked Inheritance

Part 4Part 4

Structure and function of DNA and RNAStructure and function of DNA and RNA

Gene ExpressionGene Expression

GenomicsGenomics

DNA TechnologyDNA Technology


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Part 3Part 3

Genotype and PhenotypeGenotype and Phenotype Trait InheritanceTrait Inheritance Beyond Inheritance PatternsBeyond Inheritance Patterns Sex-linked InheritanceSex-linked Inheritance


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Genotype and PhenotypeGen

otype and PhenotypeEach individual has aEach individual has a GENOTYPEGENOTYPE , or their own specific genes. They inherited these, or their own specific genes. They inherited these

genes from their parents. Each parent contributes angenes from their parents. Each parent contributes an ALLELEALLELE , specifying an offspring's, specifying an offspring'sanatomical and physiological characteristics. Alleles designate specific traits and areanatomical and physiological characteristics. Alleles designate specific traits and are

therefore denoted as follows:therefore denoted as follows: DOMINANT ALLELESDOMINANT ALLELES (specific capital letter) and(specific capital letter) andRECESSIVE ALLELESRECESSIVE ALLELES (same specific lower case letter). An alleles position on a(same specific lower case letter). An alleles position on a

chromosome is known as its LOCUS, or its designated space.chromosome is known as its LOCUS, or its designated space.

HOMOZYGOUS DOMINANT:HOMOZYGOUS DOMINANT: Two dominant allelesTwo dominant alleles

HOMOZYGOUS RECESSIVE:HOMOZYGOUS RECESSIVE: Two recessive allelesTwo recessive alleles

HETEROZYGOUS:HETEROZYGOUS: OneOnedominant and one recessivedominant and one recessive

alleleallele

The physical appearance thatThe physical appearance that

results from the allele combinationresults from the allele combinationis calledis called PHENOTYPEPHENOTYPE

Picture from HumanBiology by Sylvia S.Mader Page 422

Picture showsdifferent earlobeattaching outcomes

for HD, HR, andheterozygous


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Genotype and PhenotypeGenotype and Phenotype

Trait InheritanceTrait Inheritance Beyond Inheritance PatternsBeyond Inheritance Patterns Sex-linked InheritanceSex-linked Inheritance


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Trait Inheritance:Trait Inheritance: One-trait crossesOne-trait crossesThere are many different combinations of alleles a child could inherit. If a genotype isThere are many different combinations of alleles a child could inherit. If a genotype is

EeSs, then the possible gametes would be ES, eS, Es, es.EeSs, then the possible gametes would be ES, eS, Es, es.

Many Parents would like to know what possible physical traits their offspring may have,Many Parents would like to know what possible physical traits their offspring may have,and this can done by calculating the cross of the parents genotypes. For example, if weand this can done by calculating the cross of the parents genotypes. For example, if welooked at a Father with freckles (Ff) and a Mother with no freckles (Ff), are results wouldlooked at a Father with freckles (Ff) and a Mother with no freckles (Ff), are results would

be the following:be the following:

ff Ff

Ff FF

F

F

f

f

Egg

Sperm

Offspring

AA PUNNETT SQUAREPUNNETT SQUARE helpshelpsdetermine the differentdetermine the different

gamete combinations.gamete combinations.

The dominant phenotype in offspring isThe dominant phenotype in offspring is75% to 25% recessive phenotype75% to 25% recessive phenotype. AA

heterozygous offspring isheterozygous offspring isMONOHYBRIDMONOHYBRID if they display theif they display the

dominant trait.dominant trait.


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Trait Inheritance:Trait Inheritance: Two-trait crossesTwo-trait crossesUsing the same idea behind the Punnett Square, one can determine the

offsprings genotype/phenotype when looking at two traits. Looking at the below

example, we can see the different gamete combinations for a widows peakhairline (WW) and a straight hairline (ww), as well as short fingers (SS) andlong fingers (ss).

Picture from HumanBiology by Sylvia S.Mader Page 426

This picture illustratesall possible gamete

combinations

If a person is

heterozygous in twotraits (hairline andfingers) they are

known to beDIHYBRID .


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Trait Inheritance:Trait Inheritance: Genetic DisordersGenetic DisordersAutosomal Recessive Disorder Autosomal Recessive Disorder

If a disorder is recessive and theIf a disorder is recessive and theunaffected/asymptomatic parents areunaffected/asymptomatic parents areheterozygous, their offspring can beheterozygous, their offspring can be

affected/symptomatic with the disorder.affected/symptomatic with the disorder.

Autosomal Recessive DisordersAutosomal Recessive Disorders

TAY-SACHSTAY-SACHS is a disease where lysosomesis a disease where lysosomes

accumulate primarily in brain cells due to anaccumulate primarily in brain cells due to anenzyme deficiency, resulting in the weakeningenzyme deficiency, resulting in the weakeningof psychomotor performances.of psychomotor performances.

CYSTIC FIBROSISCYSTIC FIBROSIS is a disease where chlorideis a disease where chlorideions cannot successfully cross the plasmaions cannot successfully cross the plasma

membrane. As a result, other compounds domembrane. As a result, other compounds donot navigate across the membrane causingnot navigate across the membrane causingthick mucus to accumulate in the bronchialthick mucus to accumulate in the bronchialpassage and the pancreatic ducts.passage and the pancreatic ducts.

PHENYLKETONURIAPHENYLKETONURIA is a disease were oneis a disease were onehas a deficiency in an enzyme that brakes downhas a deficiency in an enzyme that brakes downthe phenylalanine amino acid. This disease canthe phenylalanine amino acid. This disease canaffect the development of ones nervous system.affect the development of ones nervous system.

SICKLE-CELLSICKLE-CELL is a disease that affects theis a disease that affects theshape of ones red blood cells due to theshape of ones red blood cells due to theabsence of an amino acid. The results are poor absence of an amino acid. The results are poor

blood circulation due to clogged vessels.blood circulation due to clogged vessels.

This illustration shows theprobability for affected offspring

Picture from http://en.wikipedia.org/wiki/Autosomal_dominant
http://en.wikipedia.org/wiki/Image:Autorecessive.jpg


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Trait Inheritance:Trait Inheritance: Genetic DisordersGenetic Disorders

Autosomal Dominant Disorder Autosomal Dominant Disorder If a disorder is dominant and both heterozygous parents displayIf a disorder is dominant and both heterozygous parents displaysymptoms, they can have a homozygous recessive offspring whosymptoms, they can have a homozygous recessive offspring whowould be asymptomatic.would be asymptomatic.

MARFANMARFAN syndrome is caused by a flaw in fibrillin, ansyndrome is caused by a flaw in fibrillin, anelastic tissue protein. Results are a caved in chest,elastic tissue protein. Results are a caved in chest,long limbs, eye and heart problems.long limbs, eye and heart problems.

HUNTINGTONHUNTINGTON disease is caused by the mutation of adisease is caused by the mutation of aprotein gene known as huntington. The result is injuryprotein gene known as huntington. The result is injuryto nerve cells and erosion of brain cellsto nerve cells and erosion of brain cells


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Genotype and PhenotypeGenotype and Phenotype Trait InheritanceTrait Inheritance



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Beyond Inheritance PatternsBeyond Inheritance PatternsTraits that are governed by multiple sets of alleles are known asTraits that are governed by multiple sets of alleles are known as POLYGENICPOLYGENICTRAITS.TRAITS. Any polygenic traits which can be influenced by nurture are known asAny polygenic traits which can be influenced by nurture are known as

aa MULTIFACTORIAL TRAITMULTIFACTORIAL TRAIT , such as a persons skin color and sun exposure., such as a persons skin color and sun exposure.

INCOMPLETE DOMINANCEINCOMPLETE DOMINANCE is theis theresult of an offspring inheriting anresult of an offspring inheriting an

intermediate phenotype from twointermediate phenotype from twohomozygous parents.homozygous parents.CODOMINANCECODOMINANCE is the result of bothis the result of bothalleles in a particular gene beingalleles in a particular gene beingpresent in a heterozygous offspring.present in a heterozygous offspring.

More than two alleles to a trait canMore than two alleles to a trait cancause an offsprings gene to havecause an offsprings gene to havemultiple outcomes. This is known asmultiple outcomes. This is known as MULTIPLE ALLELE INHERITANC.MULTIPLE ALLELE INHERITANC.

Picture from http://www.emc.maricopa.edu/faculty/farabee/BIOBK/incomdom.gif

Picture of incomplete dominance: Redflower and White flower = Pink flowers


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Genotype and PhenotypeGenotype and Phenotype Trait InheritanceTrait Inheritance



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Sex-linked InheritanceSex-linked InheritanceSEX-LINKEDSEX-LINKED traits are controlled on sex chromosomes;traits are controlled on sex chromosomes; X-LINKEDX-LINKED alleles arealleles are

found on x chromosomes, whereasfound on x chromosomes, whereas Y-LINKEDY-LINKED alleles are found on yalleles are found on ychromosomes. In order for a female (xx) to receive a sex-linked disorder, theychromosomes. In order for a female (xx) to receive a sex-linked disorder, theywould have to receive two recessive alleles (one from each parent); however awould have to receive two recessive alleles (one from each parent); however a

male (xy) only receives one allele because he only has one X-link.male (xy) only receives one allele because he only has one X-link.

Color blindness, muscular dystrophy (muscle deterioration disease), andColor blindness, muscular dystrophy (muscle deterioration disease), and

hemophilia (disease that affects ability to clot blood) are all X-linked recessivehemophilia (disease that affects ability to clot blood) are all X-linked recessivedisorders. The above table shows the chance of having a colorblind child.disorders. The above table shows the chance of having a colorblind child.

Picture fromHuman Biologyby Sylvia S.Mader Page436


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Part 4Part 4

Structure and function of DNA & RNAStructure and function of DNA & RNA Gene ExpressionGene Expression GenomicsGenomics DNA TechnologyDNA Technology


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Overview of DNA & RNA Structure and FunctionOverview of DNA & RNA Structure and Function

DNA: Deoxyribonucleic AcidDNA: Deox yribonucleic Acid

Contains five carbon sugar Contains five carbon sugar deoxyribosedeoxyribose

Bases Adenine (A), ThymineBases Adenine (A), Thymine(T), Guanine (G), and Cytosine (C)(T), Guanine (G), and Cytosine (C)

Base can have two rings (A andBase can have two rings (A andG) or one ring (T and C)G) or one ring (T and C)

Possesses genetic information inPossesses genetic information incellscells

Copy and distribute geneticCopy and distribute geneticinformation duringinformation duringcellular/organism reproductioncellular/organism reproduction

Double stranded/helix/Double stranded/helix/Base pairingBase pairing

RNA: Ribonucleic AcidRNA: Ribonucleic Acid

Contains five carbon sugar ribose

Base (U) replaced base (T)

Does not form helix/singlestranded

DNA is rewritten in RNA formwhich allows it to be transferred

to other parts of the cell withamino acid sequence information

Protein synthesis

NUCLEOTIDE:NUCLEOTIDE: Molecular structure consisting of three subunit molecules a phosphate,Molecular structure consisting of three subunit molecules a phosphate,a sugar (sugar deoxyribose or ribose) and a nitrogenous base. DNA/RNA are polymersa sugar (sugar deoxyribose or ribose) and a nitrogenous base. DNA/RNA are polymers

Picture from Human Biology by Sylvia S. Mader Page 444


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DNA & RNA Structure and FunctionDNA & RNA Structure and Function

Complementary Paired Bases:Adenine (A) and Thymine (T),Guanine (G) and Cytosine (C)

Sugar and Phosphate supportmolecules: Contains five carbonsugar deoxyribose

Picture from Human Biology by Sylvia S. Mader Page 444


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Replication of DNADuplicating a DNA helix is known as DNA REPLICATION . As DNA replicates itself, it

uses one of the original strands of the helix as a TEMPLATE in the formation process.

The result is an original strand for each of the new strands. An enzyme helps in breakingthe hydrogen bonds and releasing the bases. New DNA nucleotides fit into their complementary paired bases. Before the two double-helix molecules are complete their

support ladder is sealed by an enzyme to protect against breakage.

Parental DNA

New Nucleotides

Replicated DNA, one parental strand in each

Picture from Human Biology bySylvia S. Mader Page 445


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Structure and Function of RNAStructure and Function of RNARIBOSOMAL RNA:RIBOSOMAL RNA: Produced in nucleolus; combines with proteinsProduced in nucleolus; combines with proteinsto make ribosome subunits. Travels to cytoplasm before proteinto make ribosome subunits. Travels to cytoplasm before proteinsynthesis. [rRNA]synthesis. [rRNA]

MESSENGER RNA:MESSENGER RNA: Produced in nucleus; transports geneticProduced in nucleus; transports geneticinformation to ribosomes in cytoplasm. [mRNA]information to ribosomes in cytoplasm. [mRNA]

TRANSFER RNA:TRANSFER RNA: Produced in nucleus; delivers amino acids toProduced in nucleus; delivers amino acids toribosomes, forming proteins. [tRNA]ribosomes, forming proteins. [tRNA]

Overview of Protein Structure andOverview of Protein Structure andFunctionFunction

Proteins are made up of amino acids

Different amino acid sequences producedifferently structured proteins

Proteins are responsible for determiningother cells configurations and duties

Some proteins are enzymes which aid in cellreaction speeds Pictures from Human Biology bySylvia S. Mader Page 34


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Structure and function of DNA & RNAStructure and function of DNA & RNA

Gene ExpressionGene Expression GenomicsGenomics DNA TechnologyDNA Technology


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Gene ExpressionGene Ex pressionTRANSCRIPTIONTRANSCRIPTION : First step in gene expression. A mRNA makes a copy of a sequence of : First step in gene expression. A mRNA makes a copy of a sequence of

nucleotides and delivers it to ribosomes. Before the mRNA can enter the cytoplasm it must benucleotides and delivers it to ribosomes. Before the mRNA can enter the cytoplasm it must beprocessed from a primary to a mature mRNA. To process the primary mRNAs, the introns (piece of processed from a primary to a mature mRNA. To process the primary mRNAs, the introns (piece of

DNA that is not part of gene) are removed leaving only the exons (segment piece is expressed).DNA that is not part of gene) are removed leaving only the exons (segment piece is expressed).TRANSLATIONTRANSLATION : The mRNAs copied sequence is translated into an amino acid sequence. The: The mRNAs copied sequence is translated into an amino acid sequence. The

outcome is theoutcome is the GENETIC CODEGENETIC CODE . The genetic code is a. The genetic code is a TRIPLET CODETRIPLET CODE because the four basesbecause the four bases(U,C,A,G) supply various triplets combination.(U,C,A,G) supply various triplets combination. CODONSCODONS are three letter mRNA units; there is aare three letter mRNA units; there is astart and a stop codon on each protein sequence. After the code is translated, tRNA deliver thestart and a stop codon on each protein sequence. After the code is translated, tRNA deliver theamino acids to the ribosome. The amino acids bind to one end of the tRNA while a three baseamino acids to the ribosome. The amino acids bind to one end of the tRNA while a three base

complimentary (mRNA codon) binds to the other end of the tRNA. In the ribosome, the mRNAscomplimentary (mRNA codon) binds to the other end of the tRNA. In the ribosome, the mRNAscodon bonds with the tRNAs anticodon.codon bonds with the tRNAs anticodon.

Picture shows how primarymRNA is processed into maturemRNA by removing the introns.

Pictures from Human Biology by Sylvia S. Mader Page 449


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Gene Expression:Gene Ex pression: Polypeptide SynthesisPolypeptide Synthesis

INITIATION:INITIATION: mRNA first fuses tomRNA first fuses tosmaller ribosomal subunit andsmaller ribosomal subunit andthen to the larger one with thethen to the larger one with thefirst tRNA.first tRNA.

ELONGATION:ELONGATION: tRNA at P-site,tRNA at P-site,Polypeptide gets longer, another Polypeptide gets longer, another tRNA arrives at A-site and takestRNA arrives at A-site and takestransferred peptide by movingtransferred peptide by movinginto P-site. Cycle starts againinto P-site. Cycle starts againwith one tRNA outgoing and awith one tRNA outgoing and anew one coming into A-site.new one coming into A-site.

TERMINATION:TERMINATION: Synthesis stopsSynthesis stopswhen ribosome reaches stopwhen ribosome reaches stopcodon.codon.

POLYRIBOSOME:POLYRIBOSOME: Group of ribosomes on one mRNA thread at a time.Group of ribosomes on one mRNA thread at a time.

Steps for Polypeptide Synthesis

1. Initiation

2a. Elongation:polypeptide is transferred

to tRNA-amino acid

2b. Elongation:ribosome moved, tRNA

at P-site longer

3. Termination

Pictures from Human Biology bySylvia S. Mader Page 451


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Regulation of Gene ExpressionRegulation of Gene Expression

NUCLEUSNUCLEUS

Transcription Control:Transcription Control: TheThetranscription control is a mechanismtranscription control is a mechanismwhich controls what genes and howwhich controls what genes and howmuch of the genes can bemuch of the genes can betranscribed.transcribed.

Posttranscriptional Control:Posttranscriptional Control: After After DNA is copied (mRNA is made),DNA is copied (mRNA is made),posttranscriptional controls theposttranscriptional controls the

processing and release of mRNAs.processing and release of mRNAs.

CYTOPLASMCYTOPLASM

Translational Control:Translational Control: ControlsControlsmRNAs abilities to bind tomRNAs abilities to bind toribosomes, their longevity inribosomes, their longevity in

cytoplasm, and further adjustmentscytoplasm, and further adjustmentsneeded prior to translation.needed prior to translation.

Posttranslational Control:Posttranslational Control:Modifications to control proteinModifications to control proteinfunction; controls adjustments tofunction; controls adjustments to

polypeptides after proteinpolypeptides after proteinsynthesis.synthesis.

Most of an organisms cells contain the same genes; however there are different types of Most of an organisms cells contain the same genes; however there are different types of cells in the body, such as muscle cells, which express different genes. Thus, whatcells in the body, such as muscle cells, which express different genes. Thus, what

makes cells differ from one another is what genes they each transcribe and translate.makes cells differ from one another is what genes they each transcribe and translate.


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Structure and function of DNA & RNAStructure and function of DNA & RNA Gene ExpressionGene Expression

GenomicsGenomics DNA TechnologyDNA Technology


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GenomicsGenomics The field that studies an organisms genome, or gene expression patterns, is knownThe field that studies an organisms genome, or gene expression patterns, is known

asas GENOMICSGENOMICS . A thirteen year long project known as the. A thirteen year long project known as the HUMAN GENOMEHUMAN GENOMEPROJECTPROJECT has helped the scientific field advance their understandings of the order of has helped the scientific field advance their understandings of the order of

bases and has given rise to thebases and has given rise to the PERSONAL GENOME PROJECTPERSONAL GENOME PROJECT where in thewhere in thefuture, individuals will be able to have their own genome sequenced.future, individuals will be able to have their own genome sequenced.

PROTEOMICS:PROTEOMICS: A field that studies cellular A field that studies cellular proteins; more specifically their arrangement andproteins; more specifically their arrangement andduties.duties.

BIOINFORMATICS:BIOINFORMATICS: The use of computer The use of computer technology in the study of genomics.technology in the study of genomics.

Did You Know A Persons Genome Can BeDid You Know A Persons Genome Can BeModified?Modified?

Gene therapy is the process of treating disorders byGene therapy is the process of treating disorders bythe injection of genetic material. This can be donethe injection of genetic material. This can be doneEX VIVOEX VIVO , by modifying cells or tissues outside the, by modifying cells or tissues outside the

body and then introducing it into the organism, or body and then introducing it into the organism, or ININ

VIVOVIVO, where the modification is injected directly into, where the modification is injected directly intoan organism.an organism.

This picture

demonstrates theEx Vivo genetherapy

Pictures from Human Biology by Sylvia S. Mader Page 456


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Structure and function of DNA & RNA Gene Expression

Genomics DNA Technology


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DNA TechnologyDNA Tec hnologyToday, scientists are adding genes to plants, animals, and bacteria to produceToday, scientists are adding genes to plants, animals, and bacteria to produce

biotechnology products.biotechnology products.

BIOTECHNOLOGY PRODUCTSBIOTECHNOLOGY PRODUCTS

are the results fromare the results from

TRANSGENETIC ORGANISMSTRANSGENETIC ORGANISMS , or organisms that have been modified. Some, or organisms that have been modified. Somebiotechnology products are hormones, vaccines, bigger and more abundantbiotechnology products are hormones, vaccines, bigger and more abundant

crops and animals. Crops are genetically modified to grow faster, bigger,crops and animals. Crops are genetically modified to grow faster, bigger,brighter, containing more vitamins and minerals, and be resilient againstbrighter, containing more vitamins and minerals, and be resilient against

insects. Animals are being genetically modified to grow bigger, supplying moreinsects. Animals are being genetically modified to grow bigger, supplying morefood, and produce compatible organs for human transplant. Genetically alteredfood, and produce compatible organs for human transplant. Genetically alteredbacteria help to ensure the longevity of crops that would typically be destroyedbacteria help to ensure the longevity of crops that would typically be destroyed

due to dramatic weather changes. Bacteria is being reprogrammed to eatdue to dramatic weather changes. Bacteria is being reprogrammed to eattoxins in our environment at an accelerated rate.toxins in our environment at an accelerated rate.


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Works CitedWorks Cited"Dolly (sheep)." Wikipedia, The Free Encyclopedia . 7 Feb 2008, 01:35 UTC. Wikimedia Foundation, Inc. 7 Feb

2008

.

"Dominance relationship." Wikipedia, The Free Encyclopedia . 1 Feb 2008, 01:19 UTC. Wikimedia Foundation,Inc. 7 Feb 2008

.

Mader, Sylvia S.Mader, Sylvia S. Human BiologyHuman Biology . New York: The McGraw-Hill Companies, Inc, 2008. Pages 421-464.. New York: The McGraw-Hill Companies, Inc, 2008. Pages 421-464.

The Online Biology Book. Estrella Mountain Community College. Sep 2006. Accessed 5 Feb 2008..
http://en.wikipedia.org/w/index.php?title=Dolly_%28sheep%29&oldid=189638415http://en.wikipedia.org/w/index.php?title=Dominance_relationship&oldid=188284513http://en.wikipedia.org/w/index.php?title=Dominance_relationship&oldid=188284513http://en.wikipedia.org/w/index.php?title=Dominance_relationship&oldid=188284513http://en.wikipedia.org/w/index.php?title=Dominance_relationship&oldid=188284513http://en.wikipedia.org/w/index.php?title=Dominance_relationship&oldid=188284513http://en.wikipedia.org/w/index.php?title=Dominance_relationship&oldid=188284513http://en.wikipedia.org/w/index.php?title=Dolly_%28sheep%29&oldid=189638415http://en.wikipedia.org/w/index.php?title=Dolly_%28sheep%29&oldid=189638415http://en.wikipedia.org/w/index.php?title=Dolly_%28sheep%29&oldid=189638415

Compendium Review Genetics Part 2

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