In maize chromosome number is $2n = 20$. The number of linkage groups in it shall be
$20$
$40$
$10$
$5$
A cross involving two different genera is called
In which of the sex determination both male and female have same number of chromosomes?
Frequency of Down’s syndrome increases when the maternal age is
Which of the following diseases results from the genetic inability to synthesize a single enzyme?
$A$ $Y-$linked gene is responsible for hypertrichosis (long hair on ears). When an affected man marries a normal woman, what percentage of their daughters would be expected to have hairy ears?