3.6 Sex Determination Flashcards
What is the only method of producing offspring in diploid eukaryotes?
sexual reproduction
What is fertilization?
successful fusion of gametes from both parents
What are heteromorphic chromosomes?
X and Y chromosomes in mammals; different in many ways
What is sex Determination?
determing the biological sex of an individual upon birth
What is responsible for sex determination in humans?
genes on sex chromosomes as well as some on autosomal chromosomes
When was is possible to show that sex determination what related to a specific chromosome?
when karyotyping became possible
Which chromosome is smaller; X or Y?
Y
What determines maleness?
the presence of the Y chromosome
When does sex differentiation occur in an embryo and how?
week 7; Y chromosome triggers testicular development on ridge cortex
What does the presence of the Y chromosome also do other than stimulating testicular development?
inhibits formation of the female reproductive system
How many genes are on the Y chromosome and how many are on the X?
Y = 75
X = 900-1400
What is the SRY?
sex determining region
Where is the SRY located?
short arm of Y chromosome
What does the SRY encode for?
testis-determining factor
What does the TDF do?
drives the initiation of male gonads in the embryo and suppresses the production of female gonads
