A pea plant that has the genotype RrGgwwdd is crossed to a pla...

Question

A pea plant that has the genotype RrGgwwdd is crossed to a plant that has the rrGgWwDd genotype. The R gene controls round versus wrinkled seed, the G gene controls yellow versus green seed, the W gene controls purple versus white flower, and the D gene controls tall versus short plants. Determine the following;

What proportion of the progeny are expected to have the genotype RrGGwwDd?

What proportion of the progeny are expected to have the genotype RrGGwwDd?

Accepted Answer

Hey, everyone. Let's take a look at this question together. If we cross an organism with big E little E big F big F big G little G N little, E little E big F little F big G big G genotypes. What is the probability of producing a big E little E big F little F big G big G genotype. Is it answer choice? A one half answer. Choice, B one third answer, choice, C 1/8 or answer choice. D 3/4 let's work this problem out together to try to figure out which of the following answer choices is the correct answer. So in order to solve this question, we have to set up three separate puna squares where we cross each trait of the genotype to get the probability of each which we can then multiply together to get the final probability of producing that final genotype. For our first puit square, we will be crossing this heterozygous four E with the homozygous recessive or E which we can represent here, we have that heterozygous of E in the top. And on the left side, we have the homozygous dominant of E which when we do the cross in the pundit square. We end up with our results as shown on the screen where we have 50% heterozygous and 50% homozygous recessive. And we want to find out what the probability of producing that heterozygous genotype for E in this cross, which we can see on our screen in the pundit square is represented as one half for that heterozygous genotype of trait E. And in our next pundit square, we will do the cross between that homozygous dominant of F with that heterozygous for F. And so in the top of the pundit square, we put that Homozygous dominant. And on the left side, we put the heterozygous and we end up with another 50% homozygous dominant and 50% heterozygous cross in the F cross which we want to find out the probability of getting that heterozygous four F. And we can see in our punt square four F, we have one half again or F. And lastly, we do a cross for that heterozygous four G with that homozygous dominant. So we will put that heterozygous in the top of our third punt square. And on the left, we put that Homozygous dominant and we end up with another 50% homozygous dominant and 50% heterozygous or the trait G, which we want to find the probability of the homozygous dominant. And we can see from our third and final pundit square that we have another one half of the offspring being homozygous dominant. So in order to find the probability of all three traits, since we want to find out all three traits together, we multiply all of our probabilities together, which we know we have one half, multiplied by one half, multiplied by another one half. Since we have one half for E, one half, for F and one half, four G, which when we multiply all three of them together, we end up with 1/8 which is answer choice C the correct answer. Because when we across these two organisms, the probability of producing that final genotype is represented as 1/8 because we do each individual traits on it square and multiply each probability together to give us that 1/8 which is answer choice C the correct answer. I hope you found this video to be helpful. Thank you and goodbye.

Key Concepts

Genotype and Phenotype

Punnett Square

Independent Assortment

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