BIOCHEM 390G Lecture Notes - Lecture 5: Product Rule, Mendelian Inheritance, Dominance (Genetics)

• School: UMASS-Amherst
• Department: Biochemistry & Molecular Bio.
• Course: BIOCHEM 390G
• Professor: Tyler Ludmilla

Document Summary

Sex chromosomes: most animals and many plants show sexual dimorphism, in other words, individuals are either male or female. Sex-linked pattern of inheritance: cytogenetics divide the x and y chromosomes into homologous and differential regions. In males, the genes in the differential regions are said the be hemizygous. In the sense that these regions are homologous, they are autosomal-like, and so they are called pseudoautosomal regions 1 and 2. X-linked inheritance: sex-linked inheritance regularly shows different phenotypic ratios in the two sexes of progeny, as well as different ratios in reciprocal crosses. In human pedigrees, an autosomal recessive disorder is generally revealed by the appearance of the disorder in the male and female progeny of unaffected parents. In the pedigree analysis of rare x-linked recessiveness, a normal female of an unknown genotype is assumed to be homozygous unless there is evidence to the contrary: duchenne muscular dystrophy (dmd) is a fatal x-linked recessive disease.