Question

Question 22 14 pts One of the most visible examples of X-inactivation is a calico cat, which has the genotype Xºxb. A calico mother and an orange father have a litter of kittens, and to everyone's surprise, one of the kittens appears to be male but has a calico pattern. Explain how this might happen and what specific genotype is most likely responsible. (if you want to use superscript in your notation like I did, it's the little "T" button on the text control panel next to the icon for choosing text and highlighting colors) 12pt Paragraph В І U Av Tv ... р O words Question 23 14 pts O a 3 ? 8:59 PM 7/30/2020

Answer 1

Let X^o be the allele for orange colour and X^b the allele for calico colour.

parents --

phenotype-- calico mother x orange father

genotype-- X^oX^b x X^oY

gametes-- X^o, X^b X^o, Y

	Xo	Xb
Xo	XoXo - orange female	XoXb - calico female
Y	XoY - orange male	XbY - calico male

The inactivation of the X^o allele by the dosage compensation may have contributed to the formation of the calico male progeny. According to the lyonisation, one of the X chromosome from either maternal or paternal origin will be deactivated and the same will be remained inactivated for all the other descending cells. this happens in order to balance the gene in both males and females. in the calico male progeny by dosage compensation the X^o allele from the maternal origin is inactivated and only X^b is remaining giving the calico pattern.