Explain the following terms with example
$(a)$ Co-dominance
$(b)$ Incomplete dominance
$(a)$ Co- dominance
Co-dominance is the phenomenon in which both the alleles of a contrasting character are expressed in heterozygous condition. Both the alleles of a gene are equally dominant. $ABO$ blood group in human beings is an example of codominance. The blood group character is controlled by three sets of alleles, namely, $I^{A}, I^{B},$ and $i .$ The alleles, $I^{A}$ and $I^{B},$ are equally dominant and are said to be co-dominant as they are expressed in $\mathrm{AB}$ blood group. Both these alleles do not interfere with the expression of each other and produce their respective antigens. Hence, $AB$ blood group is an example of co-dominance.
$(b)$ Incomplete dominance
Incomplete dominance is a phenomenon in which one allele shows incomplete dominance over the other member of the allelic pair for a character. For example, a monohybrid cross between the plants having red flowers and white flowers in Antirrhinum species will result in all pink flower plants in $\mathrm{F}_{1}$ generation. The progeny obtained in $\mathrm{F}_{1}$ generation does not resemble either of the parents and exhibits intermediate characteristics. This is because the dominant allele, $R$, is partially dominant over the other allele, $r$. Therefore, the recessive allele, $r,$ also gets expressed in the $\mathrm{F}_{1}$ generation resulting in the production of intermediate pink flowering progenies with $Rr$ genotype. (figure)
A man with blood group $‘A’$ marries a woman with blood group $‘B’$. What are all the possible blood groups of their offsprings?
$ABO$ 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?
The most popularly known blood grouping is the $ABO$ grouping. It is named $ABO$ and not $ABC$, because ' $O$ ' in it refers to having
For a child having blood group $B$, if father has blood group $A$, what may be the blood group of the mother
Identify the wrong statement with reference to the gene $'I'$ that controls $ABO$ blood groups.