The affected male in the pedigree chart is symbolised by

Select the correct options for the given statements:
Statements:
$X$: Formation of Haemoglobin is controlled by two closely linked genes $HBA1$ and $HBA2$ on chromosome $16$ of each parent.
$Y$: $\beta$-Thalassemia is controlled by a single gene $HBB$ on chromosome $21$ of each parent.

What does the given symbol represent?

$A$ color-blind daughter is born only when:

In Huntington's disease,the unaffected persons are homozygous for normal allele $h$. The following pedigree is erroneous because:

$A$: The possibility of a female becoming a haemophilic is extremely rare.
$R$: Mother of such a female has to be a carrier and the father should be haemophilic.