Question

HELP WITH GENETICS PLEASE!!!***Sex Linkage Questions In humans, colorblindness is a sex-linked trait. Jordan and Jill are a married couple with two sons, Jordan Jr. and James. James is colorblind, but none of James’ grandparents are colorblind and neither is Jordan Jr. Jordan and Jill have a third child, a daughter name Jess. Jess is colorblind just like her brother James. Given this information, answer the following questions.

1.) What chromosome is the gene for colorblindness located on? Explain why you drew this conclusion.

2.) Is either Jordan, Jill, or both Jordan and Jill colorblind? Explain your answer.

3.) Given the information you know about their grandchildren, can you determine the genotypes for all four of Jessica’s grandparents? If so, what are they?

4.) Jess’s friend Julie is also colorblind; however, neither of Julie’s parents are colorblind. Can Julie’s mom and dad both be her biological parents? Explain your answer.

Answer 1

1.) What chromosome is the gene for colorblindness located on? Explain why you drew this conclusion.

Answer:

Color vision deficiency (sometimes called color blindness) represents a group of conditions that affect the perception of color. Red-green color vision defects are the most common form of color vision deficiency. Genetic changes involving the OPN1LW or OPN1MW gene cause red-green color vision defects. The OPN1LW and OPN1MW genes are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one genetic change in each cell is sufficient to cause the condition. Males are affected by X-linked recessive disorders much more frequently than females because in females (who have two X chromosomes), a genetic change would have to occur on both copies of the chromosome to cause the disorder.

2.) Is either Jordan, Jill, or both Jordan and Jill colorblind? Explain your answer.

Answer:

A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. As James is a colour blidness patient, he carries that gene from her mother Jill. So Jill may be carrier or patient. But as it has given that none of the James grandparent are colour blind. So it is confirmed that Jill must be a carrier for colour blindness.

As it is given that Jess is colour blind, so it is sure that Jordan must be a colour blindness.

3.) Given the information you know about their grandchildren, can you determine the genotypes for all four of Jessica’s grandparents? If so, what are they?​

Answer:

It has given that none of the Jessica's grandparents are colorblind.

So we have, Jordan's father genotype is not a colorblind whereas the Jordan's mother is a carrier for colorblindness

If we see the maternal grandparent's of Jessica, here is the genotype.

Jill's father is not a colorblind patient whereas her mother is a carrier for colorblindness.

4.) Jess’s friend Julie is also colorblind; however, neither of Julie’s parents are colorblind. Can Julie’s mom and dad both be her biological parents? Explain your answer.

Answer:

No, Julie’s mom and dad both can not be her biological parents.

When daughter is a colorblindness patient, the biological father must be colorblindness. Because one of he X-chromosome comes the father side. But the biological mother may be colorblindness patient or carrier.