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Question
Who explained that in early embryogenesis one of the two X-chromosomes becomes genetically inert and heteropycnotic and forms Barr body?
Who explained that in early embryogenesis one of the two X-chromosomes becomes genetically inert and heteropycnotic and forms Barr body?
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Solution
The correct option is A Mary Lyon
M. Barr and E. Bertram first observed presence of a condensed body in the nucleus of female cells only. They noticed the presence of single condensed body in normal female cats, while males show none. They named the body as sex chromatin, since known as a Barr body. Mary Lyon discovered that this Barr body is an inactive X chromosome, which in females, becomes tightly coiled into heterochromatin in early embryo genesis. Later, the phenomenon was related to dosage compensation which is accomplished by the inactivation of one of the X chromosomes in females. This is done so that both males and females have only one functional X chromosome per cell because human males have only one X chromosome, whereas females have two and hence twice the genes present on the X-chromosome. Joe-Hin Tijo and Albert Levan discovered that there was 46 chromosomes, not 48. They were working on human embryonic tissue. Hauschka worked on sex linked incompatibility. Option A is the correct answer.
M. Barr and E. Bertram first observed presence of a condensed body in the nucleus of female cells only. They noticed the presence of single condensed body in normal female cats, while males show none. They named the body as sex chromatin, since known as a Barr body. Mary Lyon discovered that this Barr body is an inactive X chromosome, which in females, becomes tightly coiled into heterochromatin in early embryo genesis. Later, the phenomenon was related to dosage compensation which is accomplished by the inactivation of one of the X chromosomes in females. This is done so that both males and females have only one functional X chromosome per cell because human males have only one X chromosome, whereas females have two and hence twice the genes present on the X-chromosome. Joe-Hin Tijo and Albert Levan discovered that there was 46 chromosomes, not 48. They were working on human embryonic tissue. Hauschka worked on sex linked incompatibility. Option A is the correct answer.
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