With reference to females, Lyon’s hypothesis refers to:
Correct Answer: Random inactivation of one of the X-chromosome through heterochromatism
Description: Ans. b (Random inactivation of one of X-chromosome through heterochromatism). (Ref. Robbin's patho-7th/178)Lyon outlined the X-inactivation, what is Lyonization commonly known as Lyon hypothesis occurs about 16th day of embryonic life. Female carriers of X- linked recessive disorders rarely affected because of random inactivation of X chromosomes in each cell.LYON'S HYPOTHESIS# "In all cells of females, one X-chromosomes is made transcriptionally inactive through heterochromatism".# It occurs on 16th day of gestation.(Q)# The inactive X can be seen in the interphase nucleus as a darkly staining small mass in contact with the nucleai membrane known as the Barr body or X chromatin. (Q)# Barr body is absent in Turners syndrome (XO). (Q)# Male with a barr body is seen in Klinefelter's syndrome. (Q)# In female with Klinefelter's syndrome, two barr bodies are present.
Category:
Pathology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now