Chapter 15 Flashcards
where are factors or genes located?
on chromosomes
what does a male?
whatever’s on his X, he will express
what is a sex-linked gene?
a gene that is located on either sex chromosome is called a sex-linked gene
Y linked genes vs. X linked genes
genes on y chromosome are Y linked (related to sex determination), genes on x chromosome are X linked (unrelated to sex)
Y linked genes vs. X linked genes
genes on y chromosome are Y linked (related to sex determination), genes on x chromosome are X linked (unrelated to sex)
where is SRY gene located?
on the Y chromosome; it is sex determining region on the Y and is responsible for development of testes in embryo
what must need to occur for a recessive X-linked trait to occur?
- a female needs two copies of the allele (homozygous)
- a male needs one copy of the allele (hemizygous)
what happens to one of the X chromosomes in females?
During embryonic development, one cell is randomly activated; the inactive X condenses into a Barr body
If a female is heterozygous for a particular gene located on the X chromosome…
she will be a mosaic for that character
linked genes tend to be…
inherited together because they are located near each other on the same chromosome
what is inherited together in fruit flies?
body color and wing size are usually inherited together in specific combinations (parental phenotypes)
what is genetic recombination?
the production of offspring with combinations of traits differing from either parent
