The number of chromosomes in Klinefelter’s syndrome is
$47\ (44 + XXY)$
$47\ (44 + XXX)$
$47\ (46 + 1\ chromosome \ 21)$
None of these
The grafting between two identical twins is known as
Barr body in mammals represents
Who gave first experimental evidence of the polygenic concept of inheritance
$A$ : Holandric traits are passed from one generation to the next generation.
$R$ : These traits appear more frequently in one sex than in other.
A hereditary disease which is never passed on from father to son is