Whatisheredity?

• Heredityisthepassingoftraitsfromparenttooffspring.

• Youinherittraitsfromyourparents

Howaretraitspassed?• Whenorganismsreproduce,traitsarepassedfromparenttooffspring.

• ThesetraitsarecarriedinDNA,thegeneticmaterial

• DNAactslikeablueprint.

publications.nigms.nih.gov

http://www.healthsystem.virginia.edu/internet/huntdisease/images/DNA.gif

Figure10.11

• ThisisaphysicalmapofthehumanXchromosome.(credit:modificationofworkbyNCBI,NIH)

• Avisibletraitormetabolicfunctionisthefinalproductofmanymolecularandbiochemicalprocesses:

• Inmostcases,informationstartswithDNAtravelingtoRNAandfinallytoprotein(ultimatelyaffectingorganismstructureandfunction).RemembertheCentralDogma?

Figure9.14

• ThecentraldogmastatesthatDNAencodesRNA,whichinturnencodesprotein.

Geneprediction

Getting to the right class…def class(animal):

""" classifies animal order by characteristics"""if hasVertebrae(animals):

if bornWithGills(animal):if developLungs(animal):

return "Amphibian"else:

return "Fish"elif warmBlooded(animal):

if hasFeathers(animal):return "Bird"

else:return "Mammal"

else:return "Reptile"

Ok.NowweidentifiedORFs.Whatisthisgoodfor?

A. DeterminetheevolutionaryoriginofgenesB. ConnectgenotypetophenotypeC. DeterminethefunctionofgenesD. LearnaboutmetabolismE. Alloftheabove

Ok.NowweidentifiedORFs.Whatisthisgoodfor?

A. DeterminetheevolutionaryoriginofgenesB. Connectgenotype tophenotypeC. Determinethefunction ofgenesD. LearnaboutmetabolismE. Alloftheabove

Wheredidanorganismcomefrom?Whatdoesanorganismlooklike?Whatdoesanorganismdo?Howdoesanorganismdoit?

Homology

AsequencedatabasesuchasGenbank couldbeusedtodoallofthefollowingEXCEPT

A)Comparecowandhumaninsulinproteinsequences.B)Predictthefunctionofanunidentifiedgenebasedonsimilargenesequences.C)Searchforgenesinafruitflythataresimilartoahumangene.D)Comparepatternsofgeneexpressionincancerousandnon-cancerouscells.

Genesà Proteins

• Proteinsà traits– Examples?

• Proteins=enzymesàmetabolism– Examples?

Figure4.11

• Metabolicpathwaysareaseriesofreactionscatalyzedbymultipleenzymes.Feedbackinhibition,wheretheendproductofthepathwayinhibitsanupstreamprocess,isanimportantregulatorymechanismincells.

Figure4.4

Genecharacteristics(GCcontent,length,codonusage,etc.)canalsotellusaboutwheregenescamefrom

Sp 1,47%GC Sp 2,38%GC

Horizontal transfer of a pathogenicity island

GC:~38%

GC:~47%

Genomic“islands”andGCcontentDue to historical horizontal transfer events, the %GC inside pathogenicity islands sometimes strongly differs from the rest of the genome.

WhichofthefollowingisanexampleofHorizontalGeneTransfer?A. Thetransmissionofaneyecolorgenefromfathertodaughter

B. Thetransmissionofageneconferringpathogenicity(theabilitytocausedisease)fromonebacterialspeciestoanother

C. Thetransmissionofageneconferringantibioticresistancefromamothercelltoitstwodaughtercells

D.Thetransmissionofatheflufromoneofyourclassmatestoyou

E. Thetransmissionofadisease-causinggenemutationfromfathertodaughter

Project1:WhatdidyoulearnabouttheSalmonellapathogenicityislandthatislinkedtoTyphoidFever?

Salmonella pathogenicity island 1

Alleles?Analleleis:

A. anotherwordforageneB. ahomozygousgenotypeC. aparticularphenotypeD. oneoftwoormorepossiblealternativeforms

ofagene

Alleles?A gene in a particular place on a particular chromosome will

express a particular trait….like flower color

Chromosome from MOM

Chromosome from DAD

Each gamete has how many alleles for a specific gene?

a. 0b. 1c. 2d. 3

DominantandRecessiveAlleles:OnetraitcanhideormaskanothertraitDominanttrait – thetraitthatalwaysshowsupwhenthealleleispresent,hidingtheothertrait

Recessivetrait – thetraitthatishiddenormaskedwheneveradominatealleleispresent

Sometraitsaredominant,somearerecessive

Mendeldiscoveredthatwhetherhispeaswereyelloworgreenisdeterminedbyasinglegeneinwhichyellow(Y)isdominantovergreen(y).Thegenotypeofyellowplantsis

A) YB) YYC) eitherYYorYyD) Yy

Figure8.12Thesepinkflowersofaheterozygotesnapdragonresultfromincompletedominance.

(credit:“storebukkebruse”/Flickr)

Bloodtypes:codominanceFigure8.13

• Ifyouwoulddescribeyourselfaswhiteorblack,yourearwaxisprobablyyellowandsticky.IfyouareEastAsianorNativeAmerican,it’slikelytobedryandwhite.

• Andforthosewiththeyellowkind,Ihatetobreakittoyou,butyourearwaxstinks.

• Don’ttakeitpersonally.Smellyearwaxisjustanotherofthegeneticquirksweinheritaspartofoneethnicgrouporanother.InnewtestsofearwaxinCaucasianandEastAsianmen,yellowearwaxfromCaucasiansgaveoffstrongerodorsthanthedry,whitekind.

• Thesamegenecontrolsbothaperson’sunderarmodorandthetypeofearwaxtheymake

AB

O

HumanABOBloodGroups

Evolutionandpopulationgenetics

• Evolutionisachangeinthecharacteristicsofapopulationoforganisms

• Behindthatphenotypicchangeisgeneticchange.

• Inpopulationgeneticterms,evolutionisdefinedasachangeinthefrequencyofanalleleinapopulation

• Allelessegregaterandomly,justlikeacoinflip,sowecanuseprobabilitytopredicttheoutcomesofgeneticcrosses(Project2)

Irisversicolor Irisvirginica Irissetosa

Traitsà species,evolutionaryrelationships