Chapter 5 A-B Flashcards
What is a linked gene?
A set of genes at different loci on the same chromosome that except for crossing over tend to be inherited together.
What is an unlinked gene?
Genes located on different chromosomes.
Do linked genes assort independently?
No, they’re a variation from 1:1:1:1 ratio in a test cross.
What is recombinant?
Chromosomes where crossing over occurred. Measures how far apart two genes are.
What are recombinant gametes and progeny?
What crossing over with linked genes that are in proximity to each other leads to
What are nonrecombinant gametes?
When there is no genetic recombination shown, this is similar to that of the original or parent DNA.
What is the recombination frequency?
recomb. progeny/Total # of progeny) x 100%
Recombination frequency = (the number of recombination progeny/total number of progeny) times 100%
When are genes not linked from a recombination frequency?
Anything over 50% is not linked.
What does it mean when genes are far apart?
The further apart the genes, the bigger the frequency.
What are the two key features of doing a two-point cross?
- Calculating the recombination frequency.
- Identify coupling and repulsion configuration of the linked genes.
What are the two most numerous phenotypes?
nonrecombinant
What are the two least numerous phenotypes?
recombinant
Coupling (cis configuration)
one chromosome contains
both wild-type alleles, one chromosome contains both mutant alleles
Repulsion (trans configuration)
wild-type allele and mutant allele are found on the same chromosome
Why should you do a chi-square test to see if numbers fit a 1:1:1:1 ratio when determining a recombination frequency?
Because the ratio of phenotypes in the progeny cannot be 1:1:1:1 in a recombination frequency.
