The genes encoding the red- and green-color-detecting proteins of the human eye are located next to one another on the X chromosome and probably evolved from a common ancestral pigment gene. The two proteins demonstrate 76 percent homology in their amino acid sequences. A normal-visioned woman (with both genes present on each of her two X chromosomes) has a red-color-blind son who was shown to have one copy of the green-detecting gene and no copies of the red-detecting gene. Devise an explanation for these observations at the chromosomal level (involving meiosis).

Question

Accepted Answer

Hey everyone, let's take a look at this question together given that brown eye color in humans is completely dominant over blue color and that a male with brown eyes carries a recessive allele that causes blue eye color and a dominant allele that causes brown eye color. Which of the following is incorrect regarding the Children's eye color if this male Weds a heterocyclic female. So since we know that the male has brown eyes and carries that recessive allele, which causes the blue eye color, that would make the male hetero zegas in his genotype. And so he Weds a hetero zegas female, so the female also has the same genotype as the male. And so when we do this cross, we end up with this as our results. And so looking at the answer choices to figure out which one is correct answer choice A. Says one half of Children will have genotype Big B. Little B. Which we know is true because we can see it here in here and that is one half with that hetero ziggy's genotype, answer choice B says 1/4 of Children will have genotype Big B. Big B. Which we know is also true because we have 1/4 with that home as a guest dominant genotype, answer choice C. Says 1/4 of Children will have genotype Little B. Little B, which is also true because we see that 1/4 of the offspring will have that homesickness recessive genotype. And so by process of elimination that would make answer choice D The correct answer, which we also know is incorrect because we only have one one child that does not have that brown eye color because brown eye color is dominant over blue eye color, and we have 123 of the four have that brown eye color, and only one has the blue eye color. So answer choice D. Is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.

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Key Concepts

X-linked Inheritance

Meiosis and Chromosomal Segregation

Gene Duplication and Homology