Chapter 4.2, Problem 29AQP

a.

Summary Introduction

To determine:

The following each type of mating indicates whether nondisjunction took place in mother or father, or whether it took place in meiosis I or meiosis II.

$\begin{array}{l}\text{a)}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{-}{\text{X}}^{-}\to {\text{X}}^{\text{a}}\text{(Turner}\text{syndrome),}\\ \text{b)}\text{}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{\text{a}}{\text{X}}^{-}\to {\text{X}}^{-}\text{(Turner}\text{syndrome),}\\ \text{c)}{\text{X}}^{\text{a}}\text{Y4}\text{×}{\text{X}}^{-}{\text{X}}^{-}\to {\text{X}}^{\text{a}}{\text{X}}^{-}\text{Y}\text{(Klinefelter}\text{syndrome),}\\ \text{d)}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{\text{a}}{\text{X}}^{-}\to {\text{X}}^{-}{\text{X}}^{-}\text{Y}\text{(Klinefelter}\text{syndrome)}\end{array}$

Introduction:

Non-disjunction occurs during cell division when chromosomes do not divide properly, it can occur in mitosis, meiosis I or II; these are three forms of non-disjunction.

Turner syndrome is a chromosomal disorder that affects females; it is a condition when females partially or completely miss their X chromosome.

Klinefelter syndrome is a genetic disorder that affects males, it results in two or more X chromosomes in males, and this condition also affects sterility and testicles.

Answer to Problem 29AQP

Non-disjunction took place in mother.

Explanation of Solution

Non-disjunction occurs during cell division when chromosomes do not divide properly, it can occur in mitosis, meiosis I or II, in this mating process, the child received no maternal X chromosomes, and the non-disjunction must have taken place in the mother, in either meiosis I or meiosis II.

Turner syndrome is a chromosomal disorder, it affects females, and it is a condition when females partially or completely miss their X chromosomes.

b.

Summary Introduction

To determine:

The following each type of mating indicates whether nondisjunction took place in mother or father, or whether it took place in meiosis I or meiosis II.

$\begin{array}{l}\text{a)}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{-}{\text{X}}^{-}\to {\text{X}}^{\text{a}}\text{(Turner}\text{syndrome),}\\ \text{b)}\text{}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{\text{a}}{\text{X}}^{-}\to {\text{X}}^{-}\text{(Turner}\text{syndrome),}\\ \text{c)}{\text{X}}^{\text{a}}\text{Y4}\text{×}{\text{X}}^{-}{\text{X}}^{-}\to {\text{X}}^{\text{a}}{\text{X}}^{-}\text{Y}\text{(Klinefelter}\text{syndrome),}\\ \text{d)}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{\text{a}}{\text{X}}^{-}\to {\text{X}}^{-}{\text{X}}^{-}\text{Y}\text{(Klinefelter}\text{syndrome)}\end{array}$

Introduction:

Non-disjunction occurs during cell division when chromosomes do not divide properly, it can occur in mitosis, meiosis I or II; these are three forms of non-disjunction.

Turner syndrome is a chromosomal disorder that affects females; it is a condition when females partially or completely miss their X chromosome.

Klinefelter syndrome is a genetic disorder that affects males, it results in two or more X chromosomes in males, and this condition also affects sterility and testicles.

Answer to Problem 29AQP

Non-disjunction took place in father.

Explanation of Solution

In this mating process, the child has not received sex chromosome from the father, so the non-disjunction took place in the father.

Turner syndrome is caused by partial or complete deletion of the X chromosome, it can be passed from one generation to another generation.

c.

Summary Introduction

To determine:

The following each type of mating indicates whether nondisjunction took place in mother or father, or whether it took place in meiosis I or meiosis II.

$\begin{array}{l}\text{a)}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{-}{\text{X}}^{-}\to {\text{X}}^{\text{a}}\text{(Turner}\text{syndrome),}\\ \text{b)}\text{}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{\text{a}}{\text{X}}^{-}\to {\text{X}}^{-}\text{(Turner}\text{syndrome),}\\ \text{c)}{\text{X}}^{\text{a}}\text{Y4}\text{×}{\text{X}}^{-}{\text{X}}^{-}\to {\text{X}}^{\text{a}}{\text{X}}^{-}\text{Y}\text{(Klinefelter}\text{syndrome),}\\ \text{d)}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{\text{a}}{\text{X}}^{-}\to {\text{X}}^{-}{\text{X}}^{-}\text{Y}\text{(Klinefelter}\text{syndrome)}\end{array}$

Introduction:

Non-disjunction occurs during cell division when chromosomes do not divide properly, it can occur in mitosis, meiosis I or II; these are three forms of non-disjunction.

Turner syndrome is a chromosomal disorder that affects females; it is a condition when females partially or completely miss their X chromosome.

Klinefelter syndrome is a genetic disorder that affects males, it results in two or more X chromosomes in males, and this condition also affects sterility and testicles.

Answer to Problem 29AQP

Non-disjunction took place in father and in meiosis I.

Explanation of Solution

Klinefelter syndrome is a genetic disorder, which affects males, it results in two or more X chromosomes in males, and it also affects the sterility and testicles.

In this mating process, the child has received both the ${\text{X}}^{\text{a}}$ and Y from the father, so the non-disjunction took place in father, in meiosis I, because ${\text{X}}^{\text{a}}$ and Y failed to separate.

d.

Summary Introduction

To determine:

The following each type of mating indicates whether nondisjunction took place in mother or father, or whether it took place in meiosis I or meiosis II.

$\begin{array}{l}\text{a)}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{-}{\text{X}}^{-}\to {\text{X}}^{\text{a}}\text{(Turner}\text{syndrome),}\\ \text{b)}\text{}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{\text{a}}{\text{X}}^{-}\to {\text{X}}^{-}\text{(Turner}\text{syndrome),}\\ \text{c)}{\text{X}}^{\text{a}}\text{Y4}\text{×}{\text{X}}^{-}{\text{X}}^{-}\to {\text{X}}^{\text{a}}{\text{X}}^{-}\text{Y}\text{(Klinefelter}\text{syndrome),}\\ \text{d)}{\text{X}}^{\text{a}}\text{Y}\text{×}{\text{X}}^{\text{a}}{\text{X}}^{-}\to {\text{X}}^{-}{\text{X}}^{-}\text{Y}\text{(Klinefelter}\text{syndrome)}\end{array}$

Introduction:

Non-disjunction occurs during cell division when chromosomes do not divide properly, it can occur in mitosis, meiosis I or II; these are three forms of non-disjunction.

Turner syndrome is a chromosomal disorder that affects females; it is a condition when females partially or completely miss their X chromosome.

Klinefelter syndrome is a genetic disorder that affects males, it results in two or more X chromosomes in males, and this condition also affects sterility and testicles.

Answer to Problem 29AQP

Nondisjunction took place in mother and in meiosis II.

Explanation of Solution

Klinefelter syndrome is a genetic disorder, aneuploidy of the sex chromosome, involving an XXY chromosomal constitution. In this mating process, the child has received two copies of X genes from the mother, hence the non-disjunction took place in mother and in meiosis II, where sister chromatids failed to separate.