BIOL 1011 Lecture Notes - Lecture 8: Abo Blood Group System, Twin, Neuromelanin
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Abo blood groups where 2 alleles and the absence of allele occur(due to glycoprotein on protein surface) 3 alleles, 4 phenotypes, and 6 genotypes. I is the absence of expression of allele. Two allele ia and ib have the same affect. The additive effect of 2 or more genes on a single phenotypic character (aabbccdd) Two or more genes affect one phenotype results from the combined expression of several genes. Eye color is determined by the amount and type of pigments, primarily melanin, present in the eye"s iris. Aa tyrosine is converted to pigment melanin. The pigment neuromelanin is found in brainstem, in dopaminergic neurons. 6. genes and behavior: smiling in infants is thought to be a genetic trait, genes for alcoholism, genes for schizophrenia. Has a genetic component and an apparent epigenetic component: for behavioral genetics, use twin studies-identical twins vs. nonidentical twins, examine polygenic traits.