A woman of blood group AB marries a man of blood group A whose father was of gro

Question

A woman of blood group AB marries a man of blood group A whose father was of group O. What is the probability that the couple will produce: a child of blood type A? two children of blood type A? a child of blood type A or B? a child of blood type AB? With regard to pattern baldness in humans, a woman who is not bald (whose mother is bald) has children with a bald man (whose father is not bald). What are their probabilities of having the following types of families? Their first child will not become bald. Their first child will be a male who will become bald. In poultry, the dominant alleles for rose comb (R) and pea comb (P), if present together, give a walnut comb. The recessive alleles of each gene, when present together in a homozygous state, give single comb. Indicate the comb characters of each parent as well as the phenotypic ratios of offspring of the following crosses. a. RRPp times rrPp rrPP times RrPp Rrpp times rrPp

Explanation / Answer

A human blood type consists of three different alleles present in the DNA of a cell. They are ABO. A mother and a father both contribute one of their 2 ABO alleles to their child.The pair of alleles in our DNA are described by Genotypes. Out of these 3 ABO, A and B are dominant alleles while O is recessive.These 3 different alleles gives 6 types of genoypes present at the genetic locus of humans which determine the phenotype or blood group.

so, we can find out the possible blood groups a child can have by knowing the blood groups of the parents. Conversely if we know the blood group of a child and one of his parents, we can calculate the blood group of other parent. From here we can say that if the man is with blood group A he may have genotypes AA(homozygous) or AO(heterozygous) and the woman has genotype AB (heterozygous)

So, the possible combination of alleles of offsprings will be:

OR

In both the cases the probability of blood type A is 50%.

a. 50%

b.Since 50% chances are of children with blood group A, two children can have the same chances of this blood group.

c.12.5%-100%

d. 75%

The combination of the blood groups acquired by offsprings will be the combination of the two tables:(1/2 A+1/2AB)*(1/2A+1/4B+1/4AB)=100%A,75% AB,12.5% B

Allele contributed by 1 parent Allele contributed by other parent Genotype of offspring Blood group of offspring A A AA A B B BB B O O OO O A B AB AB A O AO A B O BO B B A AB AB

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