Sex Determination and Sex Linkage Flashcards
What does sex refer to?
sexual phenotype
What is monoecious?
refers to the production of both male and female gametes in the same individual
What is dioecious?
refers to the production of either male or female gametes in the same individual
XX-XO system
XX-female
XO-male
XX-XY system
XX-female
XY-male
ZZ-ZW system
ZZ-male
ZW-female
Haplodiploidy systme
haploid set-male
diploid set-female
What is the genetic sex-determining system?
no sex chromosomes, only the sex-determining genes
What is the environment sex determination system?
environment factors
ex: limpet’s position in the stack, temperature in turtles
In hplodiploidy, what do males and females develop from?
males - unfertilized eggs
females - fertilized eggs
Sex determination in drosophila is based on what?
the genetic balance of the X chromosome; X chromosomes contain genes with female-producing effects while autosomes contain genes with male-producing effects
What would be the sexual phenotype of XO AA
male
What would be the sexual phenotype of XXY AA
female
What would be the sexual phenotype of XXX AA
metafemale
What would be the sexual phenotype of XXXY AA
metafemale
What would be the sexual phenotype of XX AAA
intersex
What would be the sexual phenotype of XO AAA
metamale
What would be the sexual phenotype of XXXX AAA
metafemale
What gene on the Y chromosome causes neutral gonads to develop into testes?
sry
What happens in androgen-insensitivity syndrome?
testes produce testosterone which causes embryonic tissues to develop into male characteristics, androgen receptor is encoded by a gene on the X chromosome; XY females lack the androgen receptor
What causes Turner Syndrome and what are some of the characteristics?
XO chromosome pairing; female with underdeveloped sex characteristics, low hairline, broad chest
What causes Klinefelter Syndrome and what are some of the characteristics?
XXY, XXXY, XXYY chromosome pairings; male usually with small testes, reduced facial and pubic hair, taller than normal
Mary Lyon proposed that the Barr body = ?
inactive X chromosome
When does X inactivation take place in humans?
during the first few weeks of development
X inactivation is brought about by the action of what?
X inactivation specific transcript located on X chromosome
Coating the X chromosome with Xist RNA causes what?
removal of acetyl groups from histone proteins, methylation of histones
