Condition of sex chromosomes in a male child of Down's syndrome will be
$XY$
$XXY$
$XX$
$XO$
In Drosophila melanogaster, $3$ pairs of autosomes and sex chromosomes of $XO$ type give rise to a normal male in appearance. In man, $22$ pairs of autosomes and $XO$ type of sex chromosomes form
Which one of the following conditions in humans is correctly matched with its chromosomal abnormality/linkage?
What is Down’s syndrome ? Give its symptoms and cause. Why is it that the chances of having a child with Down’s syndrome increases if the age of the mother exceeds forty years ?
Loss of a single chromosome produces a condition called.
Number of sex chromosomes is normal in