SRY gene
sex determining region of the Y chromosome. testes-specific transcription factor- plays role in sexual development in males. If missing or nonfunctional, female development occurs
transcription factors
protein that turns on other genes
x-linked recessive traits
always expressed in male, expressed in female only when homozygous, mothers can pass to sons and daughters, fathers can pass to daughters only
x-linked dominant traits
rare, more severe in males, females only need one copy to express phenotype
X inactivation
one of two X chromosomes is randomly inactivated and remains coiled as a Barr body
XIST gene
encodes an RNA that binds to and inactivates the X chromosome
Mosaics
females, some cells
express genes on maternal X
chromosome, some express genes on
paternal X chromosome
sex-limited traits
affects a structure or function of the body
that is present in only males or females. ie- ovary development in females, sperm development in males
sex-influenced traits
traits controlled by autosomal genes that are usually dominant in one sex but recessive in the other sex
genomic imprinting
difference in expression of a gene depending upon whether it was inherited from mother or father
ie- missing region of chromosome 15- if inherited from father prader willi, if inherited from mother angeleman syndrome