what is the probability of each of the following sets of parents producing genotypes in their offspring?

Question

parents=AA xaa offspring=Aa what is the probability?
parents Aa x Aa offspring=Aa what is the probability?
parents Aa x Aa offspring=aa what is the probability?
parents AaBb x AaBB offspring= AaBB what is the probabilty?
parents AaBb x AaBB offspring=AaBb what is the probability?
parents AaBb x AaBb offspring=AABB what is the probability?

Answer 1

1) AA*aa = 100% Aa

2 & 3) Aa*Aa = 50% Aa, 25% aa (also 25% AA)

For 4-6, figure the probability of the A gene result, then multiply that by the probability of the B gene result.

4) Aa*Aa = 50% Aa (.5); Bb*BB = 50% BB (.5)
.5*.5 = .25 = 25% AaBB

5) 50% Aa; 50% Bb = 25% AaBb

6) 25% AA; 50% BB = .25*.5 = .125 = 12.5%

Answer 2

You need to learn HOW to get the right answers to these kinds of problems. If you look at the first one, the parent on the left can only produce one kind of gamete (A), and the other parent can only produce one kind of gamete (a). So ALL of their offspring will be Aa.

For the second one, each parent will produce two kinds of gametes in equal numbers. So, from each parent, 1/2 of their gametes will be A and 1/2 will be a. So you could get an offspring with the genotype Aa two different ways: Aa or aA. The chance of the first combination is 1/2 X 1/2= 1/4 and the chance of the second combination is also 1/4. So, the chance of getting an Aa offspring is 2/4 of 1/2 (50%).

If you look at the 4th one AaBb X AaBB giving AaBB. You just saw that the chance of getting Aa offspring from Aa X Aa is 1/2. So, now look at the B's. The chance of Bb X BB giving Bb is 1/2. So, multiply those together and you get 1/2 X 1/2 = 1/4. That's the chance of getting AaBB from that cross.

Hope this helps you figure out the rest of them...

Answer 3

1
1/4if aA &Aa means same
otherwise it is1/3
1/4if aA &Aa means same
otherwise it is1/3
same for next two
0 for last

Answer 4

1. 100% probability
2. 50%
3. ... --> http://anthro.palomar.edu/mendel/mendel_2.htm