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What is All are true about Lyon's hypothesis except? and explain in detail?
Ans. (b) Only X chromosome from the mother undergoes pyknosisRef: Robbin's pathology 9th ed. /164Lyon hypothesis is:* Only one of the X chromosome is genetically active* Other X chromosome which can be of paternal or maternal origin undergoes pyknosis and is rendered inactive.* Inactivation of either paternal or maternal X chromosomes occurs at random among the cells of blastocyst by about 16th day of embryonic life* Inactivation of X is because of a gene called Xist which is causing gene silencing DNA methylation.