Chapter 8.2, Problem 23AQP

a.

Summary Introduction

To explain:

The proportions of progeny produced and phenotypes produced by mating between red-eyed Notch female with white-eyed male.

Introduction:

Notch mutations in Drosophila are X-linked wing mutations. One of the reasons for these mutations is chromosome deletion. Notch deletions are dominant mutations. The heterozygous flies for Notch mutations have notched wings along the edges and at the tips. This mutation is lethal in homozygous and hemizygous condition.

Explanation of Solution

Tabular representation:

Gametes	${\text{X}}^{\text{W}}$	$\text{Y}$
${\text{X}}^{\text{R}}$	$\begin{array}{l}{\text{X}}^{\text{R}}{\text{X}}^{\text{W}}\\ \left(\text{Red-eyed female}\right)\end{array}$	$\begin{array}{l}{\text{X}}^{\text{R}}\text{Y}\\ \left(\text{Red-eyed male}\right)\end{array}$
${\text{X}}^{\text{W}-}$	$\begin{array}{l}{\text{X}}^{\text{W}-}{\text{X}}^{\text{W}}\\ \left(\text{White-eyed }Notch\text{ female}\right)\end{array}$	$\begin{array}{l}{\text{X}}^{\text{W}-}\text{Y}\\ \left(\text{White-eyed }Notch\text{ male dead}\right)\end{array}$

Table.1: The progeny produced by mating of red-eyed Notch female and white-eyed male.

The locus for white eyes is covered with Notch mutations. The female is red-eyed and have Notch mutation, so her genotype would be ${\text{X}}^{\text{R}}{\text{X}}^{\text{W}-}$. The male is white-eyed, so its genotype would be ${\text{X}}^{\text{W}}\text{Y}$. The gametes formed by mating between red-eyed Notch female and white-eyed male is shown below:

$\begin{array}{ccccc}\text{Parents}& & ♂& \times & ♀\\ & \text{Genotype}& {\text{X}}^{\text{W}}\text{Y}& & {\text{X}}^{\text{R}}{\text{X}}^{\text{W}-}\\ & \text{Phenotype}& \text{White-eyed}& & \text{Red-eyed }Notch\\ & & \downarrow & & \downarrow \\ \text{Gametes}& & {\text{X}}^{\text{W}}\text{,Y}& & {\text{X}}^{\text{R}}{\text{,X}}^{\text{W}-}\end{array}$

The progeny produced by mating of red-eyed Notch female and white-eyed male can be seen in Table.1: “The progeny produced by mating of red-eyed Notch female and white-eyed male”.

$1$ lethalNotch male will die. Rest of the proportion of phenotypes will be $\frac{1}{3}$ would be red-eyed female, $\frac{1}{3}$ would be red-eyed male, and $\frac{1}{3}$ would be white-eyed Notch female.

b.

Summary Introduction

To explain:

The proportions of progeny produced and phenotypes produced by mating betweenwhite-eyed Notch female with red-eyed male.

Introduction:

Notch mutations in Drosophila are X-linked wing mutations. One of the reasons for these mutations is chromosome deletion. Notch deletions are dominant mutations. The heterozygous flies for Notch mutations have notched wings along the edges and at the tips. This mutation is lethal in homozygous and hemizygous condition.

Explanation of Solution

Tabular representation:

Table.2: The progeny produced by mating of white-eyed Notch female and red-eyed male.

Gametes	${\text{X}}^{\text{R}}$	$\text{Y}$
${\text{X}}^{\text{W}}$	$\begin{array}{l}{\text{X}}^{\text{R}}{\text{X}}^{\text{W}}\\ \left(\text{Red-eyed female}\right)\end{array}$	$\begin{array}{l}{\text{X}}^{\text{W}}\text{Y}\\ \left(\text{White-eyed male}\right)\end{array}$
${\text{X}}^{\text{W}-}$	$\begin{array}{l}{\text{X}}^{\text{R}}{\text{X}}^{\text{W}-}\\ \left(\text{Red-eyed }Notch\text{ female}\right)\end{array}$	$\begin{array}{l}{\text{X}}^{\text{W}-}\text{Y}\\ \left(\text{White-eyed }Notch\text{ male dead}\right)\end{array}$

Table.2: The progeny produced by mating of white-eyed Notch female and red-eyed male.

The female is white-eyed and has Notch mutation, so her genotype would be ${\text{X}}^{\text{W}}{\text{X}}^{\text{W}-}$. The male is red-eyed, so its genotype would be ${\text{X}}^{\text{R}}\text{Y}$. The gametes formed by mating between white-eyed Notch female and red-eyed male are shown below:

$\begin{array}{ccccc}\text{Parents}& & ♂& \times & ♀\\ & \text{Genotype}& {\text{X}}^{\text{R}}\text{Y}& & {\text{X}}^{\text{W}}{\text{X}}^{\text{W}-}\\ & \text{Phenotype}& \text{Red-eyed}& & \text{White-eyed }Notch\\ & & \downarrow & & \downarrow \\ \text{Gametes}& & {\text{X}}^{\text{R}}\text{,Y}& & {\text{X}}^{\text{W}}{\text{,X}}^{\text{W}-}\end{array}$

The progeny produced by mating of white-eyed Notch female and red-eyed male can be seen in Table.2: “The progeny produced by mating of white-eyed Notch female and red-eyed male”.

$1$ lethalNotch male will die. Rest of the proportion of phenotypes will be $\frac{1}{3}$ would be red-eyed female, $\frac{1}{3}$ would be white-eyed male, and $\frac{1}{3}$ would be red-eyed Notch female.

c.

Summary Introduction

To explain:

The proportions of progeny produced and phenotypes produced by mating betweenwhite-eyed Notch female with white-eyed male.

Introduction:

Notch mutations in Drosophila are X-linked wing mutations. One of the reasons for these mutations is chromosome deletion. Notch deletions are dominant mutations. The heterozygous flies for Notch mutations have notched wings along the edges and at the tips. This mutation is lethal in homozygous and hemizygous condition.

Explanation of Solution

Tabular representation:

Table.3: The progeny produced by mating of white-eyed Notch female and white-eyed male.

Gametes	${\text{X}}^{\text{W}}$	$\text{Y}$
${\text{X}}^{\text{W}}$	$\begin{array}{l}{\text{X}}^{\text{W}}{\text{X}}^{\text{W}}\\ \left(\text{White-eyed female}\right)\end{array}$	$\begin{array}{l}{\text{X}}^{\text{W}}\text{Y}\\ \left(\text{White-eyed male}\right)\end{array}$
${\text{X}}^{\text{W}-}$	$\begin{array}{l}{\text{X}}^{\text{W}-}{\text{X}}^{\text{W}}\\ \left(\text{White-eyed }Notch\text{ female}\right)\end{array}$	$\begin{array}{l}{\text{X}}^{\text{W}-}\text{Y}\\ \left(\text{White-eyed }Notch\text{ male dead}\right)\end{array}$

Table.3: The progeny produced by mating of white-eyed Notch female and white-eyed male.

The female is white-eyed and have Notch mutation, so her genotype would be ${\text{X}}^{\text{W}}{\text{X}}^{\text{W}-}$. The male is white-eyed, so its genotype would be ${\text{X}}^{\text{W}}\text{Y}$. The gametes formed by mating between white-eyed Notch female and white-eyed male is shown below:

$\begin{array}{ccccc}\text{Parents}& & ♂& \times & ♀\\ & \text{Genotype}& {\text{X}}^{\text{W}}\text{Y}& & {\text{X}}^{\text{W}}{\text{X}}^{\text{W}-}\\ & \text{Phenotype}& \text{White-eyed}& & \text{White-eyed }Notch\\ & & \downarrow & & \downarrow \\ \text{Gametes}& & {\text{X}}^{\text{W}}\text{,Y}& & {\text{X}}^{\text{W}}{\text{,X}}^{\text{W}-}\end{array}$

The progeny produced by mating of white-eyed Notch female and white-eyed male can be seen in Table.3: “The progeny produced by mating of white-eyed Notch female and white-eyed male”.

$1$ lethalNotch male will die. Rest of the proportion of phenotypes will be $\frac{1}{3}$ would be white-eyed female, $\frac{1}{3}$ would be white-eyed male, and $\frac{1}{3}$ would be white-eyed Notch female.

Conclusion

Notch mutation is lethal in hemizygous and homozygous condition. So males can never have Notch mutation. The proportion of phenotypes produced by mating of red-eyed Notch female with white-eyed male will be $\frac{1}{3}$ would be red-eyed female, $\frac{1}{3}$ would be red-eyed male, and $\frac{1}{3}$ would be white-eyed Notch female.

The proportion of phenotypes produced by mating of white-eyed Notch female with red-eyed male will be $\frac{1}{3}$ would be red-eyed female, $\frac{1}{3}$ would be white-eyed male, and $\frac{1}{3}$ would be red-eyed Notch female.

The proportion of phenotypes produced by mating of white-eyedNotch female with white-eyed male will be $\frac{1}{3}$ would be white-eyed female, $\frac{1}{3}$ would be white-eyed male, and $\frac{1}{3}$ would be white-eyed Notch female.