GN 311 Lecture Notes - Lecture 3: Green Sea Turtle, Heterogametic Sex, Lygaeus
Document Summary
Sex determination (more) estrogen: females (more) testosterone: males. Different temperatures and chemicals can contribute to the sex of organisms. In bees and wasps: males are haploid (unfertilized egg, females are diploid and must be heterozygous for a single multiple allele locus, on slide 73, (cid:862)s(cid:863) is lo(cid:272)us a(cid:271)(cid:271)re(cid:448)iatio(cid:374, exponents are alleles. In some reptiles and birds, there is a: zz/zw system, male is homogametic (zz, female is heterogametic (zw) Fun fact: peacock is male, peahen is female. X and y chromosomes function as homologues: these separate in anaphase i of meiosis. Lyon hypothesis for dosage compensation: sometimes x chromsomes are inactivated. Inactivated x is called a barr body: normal female: 1 x turned off, normal male: 0 x turned off, turner female: 0 x turned off, klinefelter male: 1 x turned off. X linked trait: each cell is making one colored hair, phenotypes (genotypes), black (xbxb, xby, yellow (xbxb, xby, tortoise shell (xbxb)
