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Ancestors of mammals belong to...

Ancestors of mammals belong to

A

Java ape man and Peking man

B

Peking and and Rhodersian man

C

Rhodesian man and Cro-Magnon man

D

Cro-magnon man and Neanherthal man.

Text Solution

Verified by Experts

The correct Answer is:
D
Barr Body. Discovered by Barr and Bertram (1949).Ohno and Henschka (1960) found it to be heterochromatised X-chromosome. One X-chromosome of femael (out of XX) undergoes facultative heaterochormatisation to form barr body. Therefore a normal famale has only one active X-chromosome (Lyon's hypothesis , Lyon 1961). Any of the two, paternal or maternal , X-chromosomes can becomes inactive. In heterozygous forms, variegated phenotype can develop due to inactivation of one X-chromosome in some parts and inactivation of other X-chromosome in other parts. In mammals, This X-chromosome replicates liate. However, it becomes euchromatic or normal before enerting germ-line or oogenesis.
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