traits Lecture13 Ma
complex
Darwinv Mendel
Darwin Mendel mendeland Darwin'sideasseemedincompatible
Theoryofevolutionwas presentedmechanism fornow mendel'sexperimentsdealt w discretetraits
groundbreakingbut traitsgotpassedon yellow v green wrinkledv smooth whichwere
incomplete individualspassallelesonto encodedbysinglegenes
evolutionoccursthrough theiroffspringintact darwinobserved continuoustraits beaksize
heritablechanges at particulategene inheritance bodylength encodedby manygenes polygenic
thepopulationlevel Mendel'slawsofinheritance
acrossg enerations lawofsegregation onlyoneallele Fallindidn'tunderstandtheunitofinheritance
mainmechanismof ispassedonfromeachparent to an genes mendel'sworkprovidedthe mechanism
adaptiveevolution is offspring butdarwiniantraitsdidn'tseem tobeinherited
naturalselection Lawofindependentassortment alleles
hadnoideanow at differentg enesare passed to faith Chant clearly
seethepattern
nevitablevariationwas offspringindependenty ofeachother of inheritancebio he studied quantitative
passedontooffspring ex allelesforpeacolor pea shapeare variation
inheritedindependently
Discretev QuantitativeTraits
Discretetrait a trait that has distinctvalues Quantitative continuous trait a trait that has a continuum of
ratherthan a rangeof phenotypes usually encoded phenotypes typicallyencodedby multiplegenes
byoneor a fewgenes ex bodysize height
ex colorof Mendel's peas prescence absence
of dimples etc
area frea
type
of gaitin codedbyallelesthathave no intermediate forms usuallyencoded by one or a few
Iq Quantitativetraits
traits
continuous traitsthatexhibit a widerangeofvariationin a populationoftenona continuum
Imph
fat bytheinterplayof multiplegenetic and environmental factors 1mostcomplex
traitsareencodedbymanygenes polygenic
polygenictraits multigenictrait a trait encodedby 21 genes oftenmanygenes
Themodern synthesis 1930s40s
aka synthesis ofevolution Genetics
Darwin andMendelreconciled
manyscientistsfrom differentfields convened to discusstheevolutionary mechanisms and clearedup confusionandinconsistencies
populations areunitsof evolution
mendelv darwin continuoustraits arealsocodedby particulategenes butmanygenes
mutation v selection mutations aresourcesofgenetic variationuponwhichselectionacts
naturals election mutation are not theonlyevolutionaryforces ex geneticdrift migration
micro evolutionaryprocesses suchas Drift selection mutationleadtomacro e volutionarychanges
multipleGenes contributingto a complextrait
Threeunlinked genes eachwith 2 alleles influencingtheintensity ofredcolorationoftheseed
casinginwheat
eachgeneactsindependently in a Mendelian fashion
examples ofcomplextraits human neight egg milkproduction grainyield
complex
Darwinv Mendel
Darwin Mendel mendeland Darwin'sideasseemedincompatible
Theoryofevolutionwas presentedmechanism fornow mendel'sexperimentsdealt w discretetraits
groundbreakingbut traitsgotpassedon yellow v green wrinkledv smooth whichwere
incomplete individualspassallelesonto encodedbysinglegenes
evolutionoccursthrough theiroffspringintact darwinobserved continuoustraits beaksize
heritablechanges at particulategene inheritance bodylength encodedby manygenes polygenic
thepopulationlevel Mendel'slawsofinheritance
acrossg enerations lawofsegregation onlyoneallele Fallindidn'tunderstandtheunitofinheritance
mainmechanismof ispassedonfromeachparent to an genes mendel'sworkprovidedthe mechanism
adaptiveevolution is offspring butdarwiniantraitsdidn'tseem tobeinherited
naturalselection Lawofindependentassortment alleles
hadnoideanow at differentg enesare passed to faith Chant clearly
seethepattern
nevitablevariationwas offspringindependenty ofeachother of inheritancebio he studied quantitative
passedontooffspring ex allelesforpeacolor pea shapeare variation
inheritedindependently
Discretev QuantitativeTraits
Discretetrait a trait that has distinctvalues Quantitative continuous trait a trait that has a continuum of
ratherthan a rangeof phenotypes usually encoded phenotypes typicallyencodedby multiplegenes
byoneor a fewgenes ex bodysize height
ex colorof Mendel's peas prescence absence
of dimples etc
area frea
type
of gaitin codedbyallelesthathave no intermediate forms usuallyencoded by one or a few
Iq Quantitativetraits
traits
continuous traitsthatexhibit a widerangeofvariationin a populationoftenona continuum
Imph
fat bytheinterplayof multiplegenetic and environmental factors 1mostcomplex
traitsareencodedbymanygenes polygenic
polygenictraits multigenictrait a trait encodedby 21 genes oftenmanygenes
Themodern synthesis 1930s40s
aka synthesis ofevolution Genetics
Darwin andMendelreconciled
manyscientistsfrom differentfields convened to discusstheevolutionary mechanisms and clearedup confusionandinconsistencies
populations areunitsof evolution
mendelv darwin continuoustraits arealsocodedby particulategenes butmanygenes
mutation v selection mutations aresourcesofgenetic variationuponwhichselectionacts
naturals election mutation are not theonlyevolutionaryforces ex geneticdrift migration
micro evolutionaryprocesses suchas Drift selection mutationleadtomacro e volutionarychanges
multipleGenes contributingto a complextrait
Threeunlinked genes eachwith 2 alleles influencingtheintensity ofredcolorationoftheseed
casinginwheat
eachgeneactsindependently in a Mendelian fashion
examples ofcomplextraits human neight egg milkproduction grainyield
