Chapter 15.4, Problem 1CC

Summary Introduction

To determine: The reason for occurrence of Down syndrome in a child if chromosomal translocation occurs in gonads of the child’s parents, involving attachment of  third copy of chromosome 21 to chromosome 14.

Concept introduction:

Down syndrome is caused by chromosomal aberration in which trisomy of chromosome 21 occurs. The parents of the children with Down syndrome are normal.

Chromosomal translocation is a process in which a part of chromosome does not break during meiosis and is carried to the gamete as it is.