Chapter 4.3, Problem 42AQP

a.

Summary Introduction

To determine:

The possible combinations of sex chromosome that are inherited by the couple’s children with number of Barr bodies if in the course of oogenesis, woman’s sex chromosomes undergo non-disjunction in meiosis I, the man’s chromosomes separate normally.

Introduction:

Non-disjunctioning is the failure of separation of chromosomal pair during anaphase stage of cell division. The non-disjunctioning results in extra copy of one chromosome in one gamete and no copy of chromosome in the other gamete. The failure in separation of the chromosome can occur in any of the two meiotic stages because both can result in extra chromosome or lack of chromosome in gametes.

b.

Summary Introduction

To determine:

The chromosome combinations and numbers of Barr bodies if the chromosomes separate normally in oogenesis, but nondisjunction of the sex chromosomes takes place in meiosis I of spermatogenesis.

Introduction:

Non-disjunctioning is the failure of separation of chromosomal pair during anaphase stage of cell division. The non-disjunctioning results in extra copy of one chromosome in one gamete and no copy of chromosome in the other gamete. The failure in separation of the chromosome can occur in any of the two meiotic stages because both can result in extra chromosome or lack of chromosome in gametes.