Question

Color-blindness is an X-linked recessive condition. A man with normal vision is married to a woman with normal vision, but whose dad is color-blind. The couple has a child with Klinefelter Syndrome (NOT the extreme type), and who is also color-blind. Where did the non-disjunction occur

Answer 1

The mother was a carrier of the X-linked recessive colorblind gene, which was passed to the child with Klinefelter Syndrome. Non-disjunction could have occurred in either the mother or the father. Males are more affected by color-blindness due to having only one X chromosome.

Step-by-step explanation:

The cause of color blindness in the child with Klinefelter Syndrome can be traced back to the mother, who is a carrier of the X-linked recessive colorblind gene. She inherited this gene from her color-blind father. Since the father of the child has normal vision and the mother has normal vision as well but is a carrier, her X chromosome carrying the colorblind gene was passed down to their child.

As for the non-disjunction resulting in Klinefelter Syndrome, it occurred either in the maternal meiosis, where two X chromosomes failed to separate, leading to an XXX egg that, when fertilized with a Y sperm, resulted in a XXY individual; or in the paternal meiosis, where a XY sperm was formed due to a non-disjunction and then fertilized an XX egg. Klinefelter Syndrome is characterized by the presence of an extra X chromosome in males, most commonly an XXY karyotype.

Color-blindness affects many more males than females because they have only one X chromosome. Females must inherit two color-blind alleles to express the condition. Thus, the pedigree for color blindness generally shows that unaffected daughter s could be carriers, but the affected son s are much more likely due to the male's single X chromosome.

Answer 2

The non disjunction occurs due to the presence of extra X.

Step-by-step explanation:

Klinefelter Syndrome is known or can be described as a situation in boys and men which normally resulted to the formation of small testicles. In this case, the testicles usually look smaller than normal size, and actually affects the production of testosterone.

It has been discovered that Klinefelter Syndrome only occurs in male, and usually manifest in the adulthood stage.

It is known to be caused by an extra X gene, which makes it to be XXY.