Which of the following is evidence supporting the Lyon hypothesis of X inactivation?
A)Female mammals that are heterozygous for X-linked traits are phenotypic mosaics.
B)A highly condensed structure is consistently observed in female cells,but not in normal male cells.
C)A female cat that is homozygous for coat color cannot have a calico phenotype.
D)Calico patterns of coat color are never exactly the same.
E)All of these are correct

Question

Quizplus · Accepted Answer

The Lyon hypothesis of X inactivation is supported by all the given options. A) Female mammals exhibit phenotypic mosaicism for X-linked traits due to random inactivation of one of the X chromosomes in each cell. B) The Barr body, a highly condensed X chromosome, is observed in female cells, supporting X inactivation. C) A homozygous female cat for coat color cannot be calico because the calico phenotype requires different alleles on the X chromosomes, which is an example of X inactivation leading to mosaic patterns. D) The unique calico patterns in cats are due to random X inactivation, resulting in different expressions of coat color genes in different areas.

Which of the Following Is Evidence Supporting the Lyon Hypothesis