Pick out the correct statements.
$(1)$ Haemophilia is a sexlinked recessive disease.
$(2)$ Down’s syndrome is due to aneuploidy.
$(3)$ Phenylketonuria is an autosomal recessive gene disorder.
$(4)$ Sickle cell anaemia is an $X$-linked recessive gene disorder.
$(1), (3)$ and $(4)$ are correct.
$(1), (2)$ and $(3)$ are correct.
$(1) $ and $(4) $ are correct.
$(2)$ and $(4)$ are correct.
Select incorrect statement
$(A)$ Linked genes cause absolute lethality
$(B)$ Persons affected by $PKU$ do not show mental disorder
$(C)$ $F_{2}$ ratio in codominance and incomplete dominance are same
$(D)$ Sex of male Drosophila is dependent on $Y-$chromosome
Marriages between close relatives and cousins is not advisable because
Select the correct statement:
A man can inherit his $X-$chromosome from his
Doctor's son