What is the pobability of getting the gamete ab from each of the following?

Question

1. aabb
2. Aabb
3.AaBb
4.AABb

Please anyone could help me this about genetics. Thank you

Answer 1

I could reel off the percentages, but come test time you would be stuck. This analysis calls for a punnett square. Go to the web site below, read and work the examples. You will be surprised how easy it is.

Answer 2

To figure probability one looks over the number of chances first.
The gamete only gets one out of a choice of two parental alleles. These genes are independent so can be considered separately.
Parental gene has two alleles A or a => Gamete
The question wants only a so it would be 1/2 (one is 'a' out of two alleles)
B or b => gamete is the same 1/2

#1 aabb
a or a => only allele of choice so 2/2
b or b => only allele of choice so again 2/2
1x1 = 1 or all the gametes

#2 Aabb
1/2 x 2/2 = 1/2 the gametes

#3 AaBb
1/2x1/2 = 1/4

# 4 AABb
0/2x1/2