Question

A man is suing his wife for divorce on the grounds of infidelity. Their first and second child, whom they both claim, are blood groups O and ABrespectively. The third child, whom the man disclaims, is blood type B. According to the given information, please answer the following questions: Another test was made in the MN blood group system. The third child was group M, and the man was group N. Can this information be used to support the man’s case? Whyor why not?

Answer 1

Yes the third child is not of the man.

Because the Manis of N type blood groups.

And in MN SYSTEM, both allele are codominant and there is two allele L^{​​​​​​M} and L^{​​​​​​N} .

If LMLM IS THEN THE BLOOD GROUP WILL BE M AND IF LMLM IS PRESENT THEN THE BLOOD GROUP WILL BE N AND IF LMLM IS PRESENT THEN THE BLOOD GROUP WILL BE MN.

HERE, THE MAN HAS N GROUP SO THE GENETIC COMBINATION WILL BE LNLN.

NOW THE THIRD CHILD HAS M GROUP WHOSE GENETIC COMBINATION IS LMLM.

SO, IN THIRD CHILD THERE IS NO ALLELE FROM THE MALE (FATHER) BECAUSE IN OFFSPRING, ONE ALLELE COMES FROM MOTHER AND ANOTHER COMES FROM FATHER.

BUT THERE IS NO FATHER ALLELE ,SO THE THIRD CHILD IS NOT OF THE MAN.

THA MAN IS CORRECT .