Problem Set #5 (15 pts)
Due on March 3/4
Handout #5: Meiosis/Monohybrid cross
1.
Imagine a diploid cell with 4 different chromosomes, A, B, C and D.
There are 2
different types of homologs for each chromosome, A and a, B and b, C and c, D and d.
a. (1 pt) If the diploid cell undergoes meiosis, how many possible genotypes could
there be after meiosis II (considering independent segregation only, not
crossovers) ?
16.
b.
(3 pts) List the genotypes of all these cells from part a :
ABCD
, abcd, ABCd
, abcD, ABcD, abCd, AbCD, aBcd, aBCd, AbcD, aBcD,
AbCd, aBCD, Abcd, abCD, ABcd
c.
(1 pt) If the A,B, C, and D homologs came from Mom, and a, b, c, and d came
from Dad, is it possible that a gamete created during meiosis could contain DNA
that originated from only one parent?
What is the probability of this occurrence?
1 in 8, or 12.5%
e.
(1 pts) If the original diploid cell had two copies of the same chromosome A
(instead of having two different forms, A and a), how many different genotypes
could there be after meiosis I?
8