Lecture 11 & 12 Flashcards
Y chromosome
What is the difference between X and autosomes?
- X chromosomes show dosage compensation
- Works twice as hard in males and four times as hard in female
- Leads to inactivation of one chromosome
- Mammals have only one functioning X chromosome, on a cell you can see the “barbody” to the side
CALICO CATS!!! X chrom has Orange/Black, so calico with orange and black spots sow which X is being expressed in those spots
What does only one X in males make them more susceptible to?
Recessive genetic diseases
What is recombination
When chromosomes are lined up and exchange pieces
Is there recombination in X or Y chromosomes?
Only X chromosomes undergo recombination during oogenesis
Recombination of XY leads to intersex
What are the differences of a Y chromosome?
small, very few genes
What gene is the most important for triggering male development
Sry
When is it helpful to have Y STR testing
In sexual assault case when can’t do
trace genotype across many generations
What does SRY do?
it binds to ? and changes the shape of the
What is a karyotype
The complete set of your chromosomes
What does DY indicate on locus?
That it is the same Y chromosome
What does it mean if you see two peaks on a locus for Y STR?
Sometimes the same locus is duplicated on the chromosome
How do you get around the issue of the abundance of female epithelial cells in a rape kit sample?
By using primers that bind specifically to male DNA (Y STR loci) the abundance of female DNA won’t affect the amplification of the male DNA in kit
Remember how to read panel cause he threw in a slide of it in here
What profile A or B is more difficult to evaluate and why
Deconvolute easier mixture
Remember to add picture and answer
What is an issue in rape kits that wouldn’t allow for picking up male DNA, even with differential extraction?
Males that don’t leave sperm (aspermetic)
