Progeny with blood group $‘O’$ can not be obtained in cross
$A×A$
$A×B$
$O×AB$
$B×B$
$ABO$ blood groups in humans are controlled by the gene $I$. It has three alleles $ I^A, I^B$ and $i$. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur?
A gene showing codominance has
In shorthorn cattle genes for red $(r_1)$, and white $(r_2)$ coat colour occur. Crosses between red $(r_1r_2)$ and white $(r_2r_2)$ produced $(r_1r_2)$ roan. This is an example of
$A$ child with mother of $B$ blood group and father of $AB$ group blood group, will not have the following blood group.
When dominant and recessive alleles express themselves together, it is called