Hemophilia is a recessive sexlinked trait Show through Punne

Hemophilia is a recessive sex-linked trait. Show through Punnett squares how and why females were carriers of this disorder but did not get it. Show how, since the availability of artificial clotting factor, females may now get hemophilia.

Solution

In X - linked recessive inheritance males are more prone to disease because they carry the disease trait. If the affected offspring’s mother has brother or father containing the same trait then the mother pass the trait to her offspring. The affected males produce unaffected daughters who can produce 50% affected sons. Hemophilia is the example of X - linked recessive trait.

X^h Y x X^hX

Genotypic and phenotypic ratios are 1:1:1:1

Artificial clotting factor VIII obtained from concentrated plasma or by synthetic factors through recombinant DNA technology. The clotting factor administered may be eliminated from the body with 12 to 24 hours and the hemophilia is back. Though artificial factors are administered due to their inefficiency, the males remain affected and produce carrier and affected males and females.

male/ female	Xh	Y
Xh	XhXh (female with hemophilia)	XhY (male with hemophilia)
X	XXh (female carrier)	XY (normal male)