test II

test II - Exam 2 Material Sex limited traitsH = cock...

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Exam 2 Material Sex limited traits- H = cock feathers h = hen feathers Hens can ONLY have hen feathers Sex Influenced traits Baldness-M F HH bald thinning Hh bald hair hh hair hair Penetrance- Genotype is right, but phenotype is not. % of individuals with genotype that show phenotype Incomplete penetrance- Polydactyly in humans Expressivity- how SEVERE is the phenotype, is it constant? Variable expressivity- variety of phenotypes for 1 genotype Example: Drosophila and eye shape—all have same genotype but shape can be different. Oval for 50% (WT). Imprinting- expression of a gene depends on which parent it comes from Epistasis- A gene interaction where 1 gene masks the effect of another gene at a different locus example: Enzyme I is regular for grey pigment Aa, aA, AA can code for enzyme I, aa cannot Bb, bB, BB can code for enzyme II, bb cannot recessive epistasis- functional allele is dominant AaBb x AaBb (brown snails) 9/16 A_B_ brown 3/16 A_bb grey 3/16 aaB_ white 1/16 aabb white Epistatic- one locus’ genotype masks genotype at other loci Hypostatic- locus whose genotype is masked by another genotype Sex Determination- 1) Hermann H- X body 2) Clarence McClung- X is Accessory 3) X+Y are homologs Tips of the top and bottom of chromosomes are primary/secondary pseudoautosomal regions
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Heterogametic- different gametes (XY, ZW) Homogametic- (XX, ZZ) (ZZ is M, ZW is F) Haplo/diplo- Hymenopterans (male/female) -bees, wasps, ants if haplo, 100% of same genetic material sisters share 75% of same genetic material, brothers share 50% Environmental- Sea turtles—higher temperatures lead to female (lower leads to males) Alligators—lower temperatures lead to females (higher leads to males) C. Fornicata- slipper limpet- sequential hermaphroditism—can be either M or F but not both Sex determination in X/Y species
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This note was uploaded on 04/09/2008 for the course BIOL 301 taught by Professor Eggleston during the Fall '07 term at VCU.

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test II - Exam 2 Material Sex limited traitsH = cock...

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