Lecture 9-12 Flashcards
If genes do not segregate randomly, and are linked when on the same chromosome, what is that called
recombination
What is recombination
when genes on the same chromosome are linked
What does the frequency of recombination depend on
the distance between genes
If no crossing over occurs between RL and rl genes (seperate) what are the products
seperate RL and rl genes
If crossing over occurs between RL and rl genes, what are the products
Rl and rL genes
What is the equation for frequency of recombination
total recombinants / total chromosome count
ie. 80 recombinants / (80 recombination + 920 parental) = 0.08
0.08 would be the frequency of recombination (or 8%)
When does homologous recombination occur in meiosis
prophase 1
What formation do sister chromatids take on during recombination
they come together to connect, forming a tetrad (or a bivalent) via a chiasma
What is the site of recombination called
chiasma - the site at which the tetrad connects
If genes are closer together, are they more or less likely to cross over
more likely to cross over together, which has a low likelihood of recombination
If genes are further apart, are they more or less likely to cross over
less likely to cross over together, more likely to cross over independently, which increases the possibility for recombination
How to calculate map units
total recombinants / total offspring (x100)
ie. 100 recombinants/400 total offspring (x100) = 25 map units
What would be a cis configuration of parental genes
homozygous parentals
What would be a trans configuration of parental genes
heterozygous parentals
What is the maximum amount for recombination frequency
50% (if more than 50% it wouldn’t be recombination it would be parental - parental is of higher frequency)
