Question

Suppose you examined a pedigree of a large family, going back 6 generations. In generation 5, a woman ("G5W") has a serious genetic disease--its first incidence in the family. In the next generation, three of her offspring--two boys and one girl--are affected, with one daughter unaffected. What is the most likely explanation?

Answer 1

 

Explanation:

There is found a mutation in G5W parents during the gamete formation created X-linked dominant disease allele. As the expression of the allele determines the allele that dominant or recessive. Because sometimes the allele becomes complete even then it is incomplete. In many cases, these alleles occur together or express at the same time that is called co dominance. The X-linked inheritance works differently with male and female because the male has XY chromosome and female has only XX chromosome. So a man has chances their son 50% but daughter has more or 99% chances to be inherited by the disease. Females only pass their X chromosome to each son or daughter so the chances from a female dominant inheritance 50% chances of X-linked disease.