We know that all human chromosomes are not paired. Most human chromosomes have a maternal and a paternal copy, and we have 22 such pairs. But one pair, called the sex chromosomes, is odd in not always being a perfect pair. Women have a perfect pair of sex chromosomes, both X. But men have a mismatched pair in which one is normal sized X and other is a short one Y. So women are XX, while men are XY. In the figure given below, half children wiil be boys and half will be girls. All children will inherit X chromosome from their mother regardless of whether they are boys or girls. Thus the sex of the children will be determined by what they inherit from their father. A child who inherits X chromosome from the father will be a girl( X+X=XX), while the child who inherits Y chromosome from the father will be a boy(X+Y=XY).
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We know that all human chromosomes are not paired. Most human chromosomes have a maternal and a paternal copy, and we have 22 such pairs. But one pair, called the sex chromosomes, is odd in not always being a perfect pair. Women have a perfect pair of sex chromosomes, both X. But men have a mismatched pair in which one is normal sized X and other is a short one Y. So women are XX, while men are XY. It means, half children wiil be boys and half will be girls. All children will inherit X chromosome from their mother regardless of whether they are boys or girls. Thus the sex of the children will be determined by what they inherit from their father. A child who inherits X chromosome from the father will be a girl( X+X=XX), while the child who inherits Y chromosome from the father will be a boy(X+Y=XY).
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I denotes ISOAGLUTINOGEN, it is a type of Antigen. There are 3 types of Antigen in blood, Ia, Ib, And I0/. These antigens are controlled by 1 single gene. Bernstein discovered this gene, which is responsible for 3 phenotypic results. This phenomenon is called Multiple Allelism. Presence of more than 2 alleles for gene OR a phenomenon where 1 gene has more than 2 alternatimg form in the same locus of homologous cheggomosomes. Which is reflected in Ia, Ib and IO/i cases.
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