question_answer

Study the given pedigree chart showing the pattern of blood group inheritance in a family.

(i) Give the genotype of the following.

(a) Parents

(b) The individual X in second generation

(ii) State the possible blood groups of the individual Y in third generation.

(iii) How does the inheritance of this blood group explain codominance?

Answer:

(i) (a) Parents genotype \[\begin{matrix}    {{I}^{A}}i & and & {{I}^{B}}i  \\    \downarrow  & {} & \downarrow   \\    A & {} & B  \\ \end{matrix}\]

(b) 'X' individual in second generation will be

\[{{I}^{A}}{{I}^{B}}\,\,\text{or}\,\,{{I}^{B}}i\,\,\text{or}\,\,{{I}^{A}}i\,\,\text{or}\,\,ii.\]

(ii) Possible blood groups of individual T will be group A or O.

(iii) \[{{I}^{A}}\] and \[{{I}^{B}}\] when stay together, show the phenomenon of codominance and express themselves in the presence of each other. In heterozygous   condition,   when   both alternative alleles coexist, they show codominance.