POST MENDELIAN GENETICSEXTENSION OF MENDEL’S RULESSlide 3INCOMPLETE DOMINANCESlide 5Slide 6CODOMINANCESlide 8Slide 9Slide 10Slide 11ENVIRONMENTAL EFFECTSSlide 13Slide 14POST MENDELIAN GENETICSEXTENSION OF MENDEL’S RULES•Phenotypic variation is not always due to simple dominance/recessive-ness of genesEXTENSION OF MENDEL’S RULESSome Traits Deviate from Mendelian Patterns:•Incomplete Dominance: •Co Dominance:•Environmental Effects:•Quantitative Traits:INCOMPLETE DOMINANCE•No Allele Is Completely DominantParentalgenerationRR rrXF2 generationRrSelf-fertilizationF1 generation: All Heterozygotes1/4 RR 1/4 Rr 1/4 Rr 1/4 rrRed Pink WhiteIncomplete dominance in Snapdragon flower colorINCOMPLETE DOMINANCE•Red allele = red pigment•White allele = no pigment•In heterozygous formCODOMINANCE•Two alleles specify different phenotypes, but…CODOMINANCEBlood type: •Determined by type of carbohydrate on RBC membrane •3 possible alleles:CODOMINANCEBlood Type:–With alleles: AA or AO, you have–With alleles: BB or BO, you have–With alleles: OO, you have–With alleles: AB, you haveCODOMINANCE•ABO Blood System:CODOMINANCE•Our immune system produced proteins (“antibodies”) that recognize foreign carbohydrates and causes foreign cells to clump together–A Blood has –B Blood has –O Blood hasENVIRONMENTAL EFFECTS•Environmental conditions help determine expression of genotype•Ex:ENVIRONMENTAL EFFECTS•Temp. sensitive enzyme acts at surface of body:QUANTITIVE TRAITSPolygenetic Inheritance:A result of more than one gene contributing to