lecture 15 Flashcards
genetics of sex
what are allosomes?
the sex chromosomes
what are autosomes?
non-sex chrosomes that appear in pairs whose members are homologous but differ from the other pairs of chromosomes
what sex is heterogametic/hemizygous?
males
what sex is homogatic/homozygous?
females
what are aneuploidies?
ex. XXY, Klinefelter’s –> excess genetic information
where is the sex-determining region?
on the Y chromosome at the SRY gene
what happens if the SRY protein is activated?
male sex organs begin to develop
what are the sites that contain specific genes that have no counterparts on the other sex chromosome?
differential regions
if a trait is sex-linked, are the reciprocal cross ratios for each sex the same?
no
color blindness is an X-linked trait. why does it appear more often in males?
they only have one allele for it
if a mother has an X-linked trait, which offspring will definitely express that X-linked trait?
a son, because he inherited the X chromosome from his mother
what are holandric traits?
Y-linked traits
how are holandric/Y-linked traits passed from generation to generation?
from father to son
how common are Y-linked traits compared to X-linked traits?
less common as the Y chromosome is much smaller
are sex-limited traits written as a superscript on the chromosome like sex-linked traits are?
no
