Give scientific reasons : The human male never passes on the gene for haemophilia to his son.
The gene for haemophilia is present on $X$-chromosome. $A$ male has only one $X$-chromosome which he receives from his mother and $Y$-chromosome from father. The human male passes the $\mathrm{X}$ chromosome to his daughters but not to the male progeny (son).
Sickle cell anaemia is due to
Haemolytic jaundice is caused due to a dominant gene but only $10\%$ of the people actually develop the disease. A heterozygous man marries a homozygous normal woman; what proportion of the children would be expected to develop the haemolytic disease
The best example for pleiotropy is
Match the following - (w.r.t. Pedigree analysis)
Column $-I$ | Column $-II$ |
$a.$ Solid symbol | $(i)$ Carrier of sex linked trait |
$b.$ Horizontal line between symbols | $(ii)$ Offspring |
$c.$ Horizontal line above the symbols | $(iii)$ Trait to be studied |
$d.$ Dot in centre | $(iv)$ Parents |
Haemophilia is more commonly seen in human males than in human females because