Lyons hypothesis please answer
Answers
Answer:
a hypothesis explaining why the phenotypic effect of the X chromosome is the same in the mammalian female which has two X chromosomes as it is in the male which has only one X chromosome: one of each two somatic X chromosomes in mammalian females is selected at random and inactivated early in embryonic development..
Some important information on Lyon's hypothesis:-
➤ It is Also known as Barr body technique.
➤ In this, interphasic nucleus of human female contains two X- chromosomes. ➤ In this, one of the X-chromosome becomes heterochromatin and other X- chromosome becomes euchromatin.
➤ By staining X- heterochromatin, it appear as a dense body which is called Barr body. and is also called Facultative hetrochromatin.
➤ Number of Barr body ==> (Number of X chromosomes - 1)
➤ In a Normal female (2A + XX) ==> One Barr body
➤ Normal male (2A + XY) ==> Barr body absent
➤ Turner syndrome (Sterile female) (2A + XO) ==> Number of Barr body
➤ Klinefelter syndrom (Sterile male 2A+XXY) ==> One Barr body
➤ Drum stick which occurs in blood of female ot Mammalia, is also a type of Barr body.