Chromosome Mapping Flashcards
What does independent assortment lead to?
Vast genetic variation
What are the 2 possibilities as to how chromosomes segregate during meiosis?
- Identical to the original
- New combinations
(50-50 chance it will receive maternal, 50-50 receive paternal)
What is meant by recombinants?
Combinations of alleles from paternal and maternal
What are recombinant gametes the result of?
Independent assortment
What is chiasmata?
Site crossing over
How does crossing over contribute to genetic variation?
Exchange of genes on non-sister chromatids
What are some of the conditions of genetic outcomes?
- Genes located on different chromosomes
- Physical location on the same chromosome
- Won’t segregate independently
What is an impossible genetic outcome?
More than 50% recombinants
What are linked genes?
Pairing of homologues during meiosis offers the opportunity to generate recombinant genes
What can crossing over between non-sister chromatids generate?
Recombinant chromosomes
What would be the result of two gene located relatively close to each other on a chromosomes?
Less likely to have chiasma and less likely that crossing over will occur.
Where is there high recombinant frequencies?
Genes located at the end of longer regions have more crossovers
What is the relationship between the degree of crossing over and the distance between two genes?
as the distance increases, the frequency of recombination increases
In a three-point mapping experiment what three general classes of offspring are expected (assuming crossovers occur)?
Noncrossovers, single crossovers, double crossovers
In a 3 point mapping experiment how many different genotypic classes are expected?
8
