Genetics Flashcards
The phases of the estrous:
diestrous 50-60 hours
proestrous 10-15 hours
estrous 10-15 hours = the period when the female is willing to mate - during night
postestrous 18-24 hours - some neutrophils
when does the blastocyst implant in the uterine wall?
4.5 days after conception
What happens 9 days after conception with the fetus?
The fetus is segmented. Known is somites, between 13-20 somites.
When does fur appear on the baby mouse?
After 9 days.
When does eyes and ears open on the baby mouse?
After 17 days.
How do you outbreed?
Use random mating - genetic status quo in the colony. The allel frequency in the colony is then hardy-weinberg.
How do you inbreed?
Need to breed close relatives for 20 generations.
What is a F1 hybrid?
a mix of two well known inbred strains. Use the first generation known as the F1 generation.
What is a transgene?
A gene that does not naturally occur in that species.
How do you perform a pronucleus microinjection?
You have a DNA construct which you transfer to a fertilized egg (the egg needs to still have two pronuclei).
How do you perform a sperm precursor injection?
You extract sperm progenitor cells from a male, and put a DNA construct into them. You multiply them in vitro and then put them back in the mouse again.
Name three nuclease techniques:
1) Zinc finger (binds three nucleotides)
2) Talens (one subunit binds one nuclotide)
3) Crispr-cas
Explain Cre-Flox
We start by floxing a gene of interest, floxing is done by doing targeted mutations around the gene creating 2 LoxP cutting sites. The gene can the be cut out using a recombinase. This recombinase (Cre) is put somewhere else in the genome with a tissue specific/inducable promoter. The flox mutation is in one mouse, the Cre in the other.
What is a congenic strain?
A strain which has received a mutation through back crossing.
Explain the principle of backcrossing
A undefined strain or stock with a specific mutation is mated with a well defined strain of mice. The offspring is then mated with the well defined strain again to cancel out the background and the gene of interest is still there. 8-10 generations.
