Please explain a genetics probability question that my professor asked: 1. What
ID: 54790 • Letter: P
Question
Please explain a genetics probability question that my professor asked:
1. What is the probability that the offspring of a cross between two RrYy will have round, yellow seeds OR wrinkeld green seeds? Assume that round (R) is dominant, and yellow (Y) is dominant.
-I can set up the individual punnet square, but I am having trouble understanding why the probability is out of 16 total.... please explain.I understand that OR means we have to add- I just don't get why the overall probability will have 16 in the denominator. My work so far is shown below. Thank you
R r R RR Rr r Rr rrExplanation / Answer
According to the law of independent assortment, proposed by the Mendel, each allele of different characters assorts independently to form together a single gamete. Hence, each allele of shape and color has to be taken together to form a gamete.
The below is the dihybrid cross, where both the characters alleles (shape, color) are taken together to form a punnet square instead of each character allele separately. In the given case, round and yellow are dominant characters.
The phenotypic ratio of the given cross is 9:3:3:1, where 9 are round, yellow; 3 are round, green; another 3 are wrinkled, yellow; and 1 is wrinkled, green.
So, the round, yellow are 9 in number and wrinkled, green is 1 in number.