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X-linked genes in female mammals often demonstrate ________.

A) incomplete dominance
B) nonrecombination during meiosis
C) underrepresentation in the genome
D) heterochromatin formation
E) phenotypic mosaicism

User Dex
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Final answer:

Female mammals often show phenotypic mosaicism due to random X inactivation that leads to a mosaic pattern of gene expression for X-linked genes. The correct answer to the question is E) phenotypic mosaicism.

Step-by-step explanation:

X-linked genes in female mammals often demonstrate phenotypic mosaicism. This occurs because female mammals have two X chromosomes, giving them a double genetic dose of X-linked genes. To maintain gene dosage balance with males, who have only one X chromosome, females undergo a process known as X inactivation.

Early in development, one of the X chromosomes in each cell becomes inactivated and condenses into a structure called a Barr body.

This inactivation is random, meaning that in females heterozygous for X-linked genes, some cells express one allele while others express the alternate allele, resulting in a mosaic pattern of phenotypic expression. This mosaicism can be observed in 'tortoiseshell' cats with heterozygous X-linked coat color genes. Hence, the correct option for the demonstration of X-linked genes in female mammals is E) phenotypic mosaicism.

User Bourbia Brahim
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