Color blindness is a sex-linked recessive trait. A mother with normal color vision and a color blind father have a color blind daughter. which statement is true about the offspring

B) Some of their sons can have normal color vision.

Explanation: Color Blindness is the relative inability to distinguish certain colors, which in their classic form often creates confusion between green and red.

   It is a disorder caused by a recessive gene located in the heterologous portion of the X chromosome, the Xd gene, while its dominant XD allele determines normal vision.

   The woman of genotype XDXd, although having a gene for color blindness, does not manifest the disease because it is a recessive gene. She is called the gene carrier for color blindness. The genotype XdY man, despite having the single dose Xd gene, manifests the disease by the absence of the dominant allele capable of preventing recessive gene expression.

   The XdY man is neither homozygous or heterozygous: he is a recessive hemizigote, because of the pair of genes he has only one. The XDY genotype man is dominant hemizigote.

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