While vermilion is X-linked in Drosophila and causes the eye colo...

Question

While vermilion is X-linked in Drosophila and causes the eye color to be bright red, brown is an autosomal recessive mutation that causes the eye to be brown. Flies carrying both mutations lose all pigmentation and are white-eyed. Predict the F₁ and F₂ results of the following crosses:

brown females x vermilion males

Accepted Answer

Hi everyone, let's take a look at this practice problem together. White eye color is a recessive X. Linked trait in Drosophila. Whereas red eye color is dominant, A red eyed male and a white eyed female are bred together. The probability of a female offspring with red eyes would be blank. So I color in Drosophila is X linked, meaning it's going to affect males and females differently. And recall that males have one X chromosome, one Y chromosome and females have two X chromosomes. And we are told that the red eye color in Drosophila is dominant will recall that is also known as the wild type and the alil that represents that is written as W. Plus. And so A W. Plus is the wild type. Red eye color are white eye color in Drosophila is the recessive allele which is also known as the mutant. And that ill ill is represented by just a W. So there is no plus. Alright, knowing that let's figure out the Jenna types for our male and female. So we have the male Drosophila and he has red eyes. So he will have the red eye a little and a Y chromosome. Our females are white. I excuse me, our female is white eyed and so she will have both of her lil's be white or the mutant type. Now in order to figure out the offspring, we would have to do a cross and a punnett square and the results would look like the following. And so you can see that we would have the mill a little on top and the female levels along the side. When we do the cross we get two males, The ones with the white chromosome and two females. And our question was asking us about the probability of female offspring. So we want to look at these offspring so they have one read a little and one white allele, meaning they will all have red eyes. So 100% of them have red eyes and 100% d would be our answer. The probability of a female offspring with red eyes would be 100%. All right, everyone. I hope you found this helpful and I'll see you for the next practice problem.

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