In a gene pool, along with beneficial mutations those mutations also exists which are damaging to an individual. It has been found that these mutations are irreversible because
$I.$ they have survival value
$II.$ they are acquired
$III.$ they are recessive and carried by heterozygous individuals only
$IV.$ they show genetic drift
Choose the incorrect option for given statement
$I$ and $III$
$I$ and $II$
$II$ and $IV$
Only $III$
The gene which increases the frequency of mutation in other gene is referred to as
A diseased man marries a normal woman. They get three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is
With the help of an example, differentiate between incomplete dominance and co dominance.
In which one of the following, complementary gene interaction rato of $9: 7$ is observed?
Which pair of chromosomes is concerned with Down's syndrome