An organism having the genotype AaBbCcDdEe is self-fertilized....

Question

An organism having the genotype AaBbCcDdEe is self-fertilized. Assuming the five genes assort independently, determine the following proportions:

Gametes that are expected to carry only dominant alleles.

Accepted Answer

Welcome back, everyone. Here's the next question, which of the following proportions is predicted to contain exclusively dominant alleys when an organism with genotype. Big X little X big Y big Y big Z big Z self fertilizes assuming the three genes assort independently. So let's think about the cross that's happening here. It's a self fertilization. So um two of the same genotype. So right at big X little X big Y big Y big Z big Z crossed with the same, we have three different genes that our question tells us assort independently. So to find the probability of the offspring having nothing but dominant alls, we can, rather than having to calculate out an entire pent square, we can use the product rule to say that the probability of all all being dominant, all three crosses resulting in a homozygous dominant result is the product of the individual probabilities. So let's take each gene one at a time and look at the probability that the offspring will be dominant in both uh copies of that gene. And then we multiply all three together to get our final probability. So let's look at gene X which is heterozygous So we have essentially a mono hybrid cross. Big X little X crossed with big X little X. And we know that our genotype ratio for our offspring of a mono hybrid cross is 1-2-1. And the first one here being the home was I guess dominant possibility. So that means that in this case, the probability of the offspring having two dominant alleys is 1/4. So I'm gonna put brackets around this description of the X cross and its probability of 1/ then that's going to be multiplied by the probability of our Y cross giving us a homozygous dominant offspring. So big, Y big Y crossed with big Y big Y in this case. Well, we don't need to do any calculation here. Um Both Can only give a dominant all. So in this case, 100 of the offspring will be big. Why big? Y? So that means the probability of having two dominant alls is just one. So that's our second probability. Then that will be multiplied by the probability for the Z gene producing only dominant alleys. But again, we have big Z big Z crossed with big Z big Z, 100% of the offspring will be homozygous dominant. So our probability is also one. So now for the probability of having only dominant alls or the proportion of offspring that have only dominant alls as our question phrases. It, We have 1/4, the proportion on for the X chromosome multiplied by one, the probability for the Y chromosome multiplied by one, the probably for the Z chromosome. So 1/4 multiplied by one, multiplied by one is equal to just 1/4. And that is answer choice. A 1 4th. So our proportion containing exclusively dominant alleles. When this organism with genotype, big, X little X big, Y big Y big Z big Z self fertilizes is choice a 1/4. See you in the next video.

An organism having the genotype AaBbCcDdEe is self-fertilized. Assuming the five genes assort independently, determine the following proportions:

Gametes that are expected to carry only dominant alleles.

Key Concepts

Independent Assortment

Gamete Formation

Dominant and Recessive Alleles

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