BIO 311D Lecture 1: Reviews

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9 Feb 2017
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ADDMOREINFOIFYOUGUYSWOULDLIKE.
*Unit 1
Humanshave46chromosomes
23frommom,23fromdad
44areautosomes2sexchromosomes
a2chromosomesaresexchromosomes
Chromosomesarenumberedaccordingtolengthwith#1beingthelongest.
female:xxmale:xy
44areautosomes2sexchromosomes
meiosis:gameteshave23chromosomes(1sexchromosome,22autosomes)
4haploidcells
https://in.answers.yahoo.com/question/index?qid=20080826063640AAYyB4W
Mitosisoccursinalleukaryoticcelltissuesandproducesgeneticallyidenticaldaughtercells
withacompletesetofchromosomes.Inhumans,mitosisproducessomaticcellsthatarediploid,
whichmeanstheycontaintwononidenticalcopiesofeachofthetwentythreechromosomes.One
copyisderivedfromtheperson'smotherandtheotherfromtheperson'sfather.
Meiosis,ontheotherhand,occursonlyintestisandovarytissues,producingspermand
ova(eggs).Thegametesthatareproducedbymeiosisinhumansarehaploid,containingonlyone
copyofeachofthetwentythreechromosomes.Becauseofrecombinationandindependent
assortmentofparentalchromosomes,thedaughtercellsproducedbymeiosisarenotgenetically
identical.
Inmitosis,oneroundofDNAreplicationoccurspercelldivision.Inmeiosis,oneroundof
DNAreplicationoccursforeverytwocelldivisions.Prophaseinmitosistypicallytakesaboutthirty
minutesinhumancells.ProphaseinmeiosisIcantakeyearstocomplete.
homologouspairs:(samechromosomefromeachparent)(23pairs)
meiosisguaranteesgeneticcontinuityfromonegenerationtoanother
diploid:2setsofchromosomes(2)(2n)2n=46
haploid:gametes;1setofchromosomes(1)
chromosomes:2chromatids
prophase1:homologouschromosomespairup.Crossingoveroccurs.
metaphase1:homologouschromosomepairsmeetatequator
anaphase1:homologouschromosomesseparate(chromosomaldisjunction)
telophase1:chromosomegetpulledtothepoles(1ofeachkind)>creates2cells
prophase2:chromosomesgetsmaller/widerindividualchromosomeslineupontheequator
metaphase2:chromosomesmeetatequator(nopairs)
anaphase2:chromatiddisjunction(2chromatidssplit)
telophase2:eachcellhas1ofeachchromatid
eachgameteresultsinhavingoneofeachchromosome
nondisjunction:Whenhomologousdon’tseparatecorrectly
normal2n=4
problematic(toomany/fewchromosomes)(Reductionalnondisjunction)
● n1=1
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ADDMOREINFOIFYOUGUYSWOULDLIKE.
● n+1=3
trisomic47chromosomes
● downsyndrome(increasedwhenmothersage)Chromosome21
● mostdie
● xxymale
disomic46chromosomes
monosomic45
● xo=sterilefemale
● won’tbeborn
polyploidabort(Amniocentesis)Usually36weekend
albinism(albino)(nopigment)lackofphenotype
allele:differentformsofsamegene
gene:locus(2alleles)
BloodTypes
AI^AI^AI^Ai
BI^BI^BI^Bi
ABI^AI^B
Oii
monohybridcross:crossof2identicalheterozygotes(WwxWw)
dihybridcross:AaWwxAaWw
tallpurple(TTPP)xshortwhite(ttpp)
gametes:TPxtp
TtPp
9:3:3:1
testcross:Wwxww
geneticrecombination:resultofmeiosis,creationofnewphenotypes
polygenic:manygenes,continuoustraits
intermediateoffspring
quantitativetraitex:stature,iq,height
qualitativetraitcategorical(notcontinuous)
ex:albinism,whiteorpurple
phenotypegenotype+environment
allplussesareequalineffect,equalandadditiveeffect
phenotypicvariation:geneticvariation+environmentalvariation
genotypicvariation:
heritability:proportionofthephenotypicvariationthathasageneticbasis
staturehas.8
alcoholismisheritablesoiscriminality
sisterchromatids:2copiesofasinglechromosomethathasbeenreplicated
allele:variantofsamegene
gene:segmentofdnamoleculethatcodesforacertaincharacter
locus:locationofgeneonchromosome
genotype:geneticmakeupoforganism
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ADDMOREINFOIFYOUGUYSWOULDLIKE.
phenotype:physicaltraitsofanorganism
identicaltwins(monozygotic)share100percentofgenes
identicaltwinsraisedapartdon’tsharelessgenes
fraternaltwins(dizygotic)share50%ofgenes,sameassiblings
gameticfrequency(genefrequency)allelefrequency
genotypefrequency
genotypicequilibrium
genAAAaaap
1.50.5.5=1
2.25.5.25.5=1
3.25.5.25.5=1
4.25.5.25.5=1
hardyWeinbergequilibriump^2+2pq+q^2=1
largepopulation 
nomutations
noselection
nomigration
randommating
*Selection,mutations,andrandommatingmeansthatevolutionishappening
mutation:randomchangesingeneticcodes
asageofparentsincreases,mutationrateincreases
95%harmful
cannotreachequilibriumwmutations
samplingerror:CHANCEdeviationfromtheexpectedvalue
smallerpopulation,biggersampleerror
fixedp=1
lostq=0
smallerpopulation,greaterdeviationfromonegenerationtoanother
geneticdriftrandomchangesingenefrequency,bottomofugraphismorelikelytohave
geneticdrift,smallpopulationswillhavemorechangesovertime
geneticbottleneck(cheetahs)randomchangesingenefrequencyduetoreducedpopulation
size
foundereffectassociatedwithcolonization,differencebetweenoriginalpopulateandnew
colonizedpopulation;formofsamplingerror;noexistingpopulation
randommatingchoiceofmatesindependentofgeneandphenotype/./
inbreedingmatingbetweenrelatives
positiveassortativematingmatesphenotypicallymoresimilarthanwouldbeexpectedby
chance
negativeassortativematingmatesphenotypicallymoredissimilarthanwouldbeexpectedby
chance
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