Question

A couple planning their family are aware that through the past three generations on the husband's side a substantial number of stillbirths have occurred and several malformed babies were born who died early in childhood. The wife has studied genetics and urges her husband to visit a genetic counseling clinic, where a complete karyotype-banding analysis is performed. Although the tests show that he has a normal complement of 46 chromosomes, banding analysis reveals that one member of the chromosome 1 pair (in group A) contains an inversion covering 70 percent of its length. The homolog of chromosome 1 and all other chromosomes show the normal banding sequence. Part A How would you explain the high incidence of past stillbirths?

Answer 1

The largest chromosome is chromosome 1. An issue in this chromosome generally results in serious outcomes in the resulting individual. In the genetic heterozygous state, a crossing over in the inversion loops of the male's chromosome 1 will result in the defected and unbalanced chromatids. These defects in chromosome 1 will most likely give rise to the malformed children and stillbirths.