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Multifactorial Traits Multifactorial Traits
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Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Jan 18, 2016

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Felix Parker
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Page 1: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Multifactorial TraitsMultifactorial Traits

Page 2: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

NomenclatureNomenclature

Mendelian trait- trait caused by alleles on Mendelian trait- trait caused by alleles on ____________________________

____________ trait- trait caused by more ____________ trait- trait caused by more than one gene often on different than one gene often on different chromosomeschromosomes

Multifactorial (complex) trait- trait that has Multifactorial (complex) trait- trait that has _______________________ components_______________________ components

Page 3: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Genetics vs EnvironmentGenetics vs Environment

Page 4: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Polygenic PhenotypesPolygenic Phenotypes

Continuously Continuously varyingvarying

Called a Called a quantitative traitquantitative trait

Genes are called Genes are called quantitative trait quantitative trait ________

_________ is a bell _________ is a bell curvecurve

Page 5: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Locus ModelsLocus Models

Model is based on how many loci Model is based on how many loci code for each polygenic traitcode for each polygenic trait

As the number of genes increase, so As the number of genes increase, so does the amount of phenotypes does the amount of phenotypes possiblepossible

Number of _______________ Number of _______________ determines phenotypedetermines phenotype

Page 6: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Fingerprint PatternsFingerprint Patterns

Dermal ridges form Dermal ridges form patterns of loops, patterns of loops, whorls, or archeswhorls, or arches

Mostly determined by Mostly determined by ______________________

Influenced by touching Influenced by touching fingers and toes to fingers and toes to amniotic sac during amniotic sac during early developmentearly development

Total ridge count Total ridge count (TRC)- count of ridges (TRC)- count of ridges on all fingerprints; on all fingerprints; creates bell curve creates bell curve

Page 7: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

HeightHeight

Genetics contribute ________ attainable Genetics contribute ________ attainable heightheight

Environment determines height actually Environment determines height actually attainedattained

Page 8: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Eye ColorEye Color Probably ______, but not multifactorialProbably ______, but not multifactorial True blue eyes- no active True blue eyes- no active

pigment; blue color comes from pigment; blue color comes from scattering of lightscattering of light

Lipochromes- greenish-blue pigmentLipochromes- greenish-blue pigment Melanins- brownish pigmentMelanins- brownish pigment Melanins tend to mask other pigmentsMelanins tend to mask other pigments Other features (flecks, specks, rings, Other features (flecks, specks, rings,

and streaks) come from distribution of and streaks) come from distribution of pigment on the irispigment on the iris

Page 9: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Skin ColorSkin Color

Color created by bits Color created by bits of melanin secreted of melanin secreted by melanocytes by melanocytes within the layers of within the layers of the skinthe skin

Variety created by Variety created by genes coding for genes coding for amount and amount and distribution of distribution of melaninmelanin

Page 10: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Cardiovascular SystemCardiovascular System

GeneticsGenetics Amount of Amount of

cholesterolcholesterol Blood pressureBlood pressure Clotting factorsClotting factors

EnvironmentEnvironment DietDiet ExerciseExercise

Page 11: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

WeightWeight

Very complex geneticallyVery complex genetically Feeling of hungerFeeling of hunger MetabolismMetabolism

EnvironmentEnvironment Diet Diet ExerciseExercise

Page 12: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Empiric RiskEmpiric Risk

Rate at which a certain trait occurs Rate at which a certain trait occurs within a _______________within a _______________

Population may be defined vaguely Population may be defined vaguely or very specificallyor very specifically

Risk may increase within certain Risk may increase within certain ethnic groups or if family members ethnic groups or if family members are affectedare affected

Page 13: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

HeritabilityHeritability

Expresses proportion of phenotype Expresses proportion of phenotype that is contributed to __________ for a that is contributed to __________ for a particular traitparticular trait

1.0 would be solely based on genetics1.0 would be solely based on genetics Lower number have ________________ Lower number have ________________

componentscomponents Number can change when Number can change when

environment changesenvironment changes

Page 14: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Coefficient of RelatednessCoefficient of Relatedness

_____________ (P)- individual based _____________ (P)- individual based relatedness is based uponrelatedness is based upon

11°- Immediate family members (mother, °- Immediate family members (mother, father, sister, brother, children); share _____ father, sister, brother, children); share _____ of genesof genes

22°- Grandparents, aunts, uncle, nieces, and °- Grandparents, aunts, uncle, nieces, and nephews, grandchildren; share _____ of nephews, grandchildren; share _____ of genesgenes

33°- Great grandparents, great aunts, great °- Great grandparents, great aunts, great uncles, great nieces, great nephews, first uncles, great nieces, great nephews, first cousins, great grandchildren; share ______ of cousins, great grandchildren; share ______ of genesgenes

Page 15: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.
Page 16: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

How do we study nature vs How do we study nature vs nurture?nurture?

Adoption StudiesAdoption Studies Adoptee is compared to adopted parents Adoptee is compared to adopted parents

(environment)(environment) Adoptee is compared to biological parents Adoptee is compared to biological parents

(genetics)(genetics) Twin StudiesTwin Studies

Prevalence of trait between MZ twins is Prevalence of trait between MZ twins is compared to DZ twins (concordance)compared to DZ twins (concordance)

Higher differences in concordance show higher Higher differences in concordance show higher differences in heritability differences in heritability

Page 17: Multifactorial Traits. Nomenclature Mendelian trait- trait caused by alleles on ______________ Mendelian trait- trait caused by alleles on ______________.

Association StudiesAssociation Studies

Researchers compare SNP’s (single Researchers compare SNP’s (single nuclear polymorphisms) between nuclear polymorphisms) between individual with and without disordersindividual with and without disorders

Groups with disorder may show a Groups with disorder may show a characteristic set of SNP’scharacteristic set of SNP’s

Can be used to find genes that are causing Can be used to find genes that are causing disorderdisorder

Can be difficult because of genetic Can be difficult because of genetic heterogeneity heterogeneity