Given below is a table showing the genotypes and the phenotypes of blo

1.	Given below is a table showing the genotypes and the phenotypes of blood groups in the human population.Sr. No.GenotypePhenotype1.(W)A2.IBi(Y)3. IA\|B(Z)4.(X)O(i) Identify the genotypes (W) and (X) and the phenotypes (Y) and (Z). (ii) How is codominance different from incomplete dominance and dominance?(iii) Name the pattern of inheritance exhibited by the phenotypes (Y) and (Z) in the table.
Answer» (i) W– I^AI^A or I^A i; X - I^oI^o or i i Y – B-group; Z – AB-group (ii) Dominance It is the phenomenon in which one allele of a gene expresses itself and suppresses the expression of the other allele (recessive) of the same gene, when they are present together in a hybrid. The hybrid resembles one of the parents. Codominance It is the phenomenon in which two alleles of a gene are equally dominant and express themselves in the presence of the other. The hybrid shows characters of both the parents. Incomplete dominance It is the phenomenon in which neither of the two alleles of a gene is completely dominant over the other. The hybrid is intermediate between the two parents. (iii) Y: The allele I^B is dominant over i and hence, the phenotype is Bgroup. So it follows law of dominance. Z: The alleles I^A and I^B are codominant and both express themselves and the phenotype is AB- group. So it follows law of codominance.

Given below is a table showing the genotypes and the phenotypes of blood groups in the human population.Sr. No.GenotypePhenotype1.(W)A2.IBi(Y)3. IA|B(Z)4.(X)O(i) Identify the genotypes (W) and (X) and the phenotypes (Y) and (Z). (ii) How is codominance different from incomplete dominance and dominance?(iii) Name the pattern of inheritance exhibited by the phenotypes (Y) and (Z) in the table.

Answer»

(i) W– I^AI^A or I^A i;

X - I^oI^o or i i

Y – B-group;

Z – AB-group

(ii) Dominance

It is the phenomenon in which one allele of a gene expresses itself and suppresses the expression of the other allele (recessive) of the same gene, when they are present together in a hybrid.
The hybrid resembles one of the parents.

Codominance

It is the phenomenon in which two alleles of a gene are equally dominant and express themselves in the presence of the other.
The hybrid shows characters of both the parents.

Incomplete dominance

It is the phenomenon in which neither of the two alleles of a gene is completely dominant over the other.
The hybrid is intermediate between the two parents.

(iii) Y: The allele I^B is dominant over i and hence, the phenotype is Bgroup. So it follows law of dominance.

Z: The alleles I^A and I^B are codominant and both express themselves and the phenotype is AB- group. So it follows law of codominance.