Chapter 5.2, Problem 25AQP

a.

Summary Introduction

To determine:

The progeny with the types of combs from the following cross $RRPP\times rrpp$.

Introduction:

The different shapes of the comb in chicken are caused due to the interaction between two different genes. This study was conducted by William Bateson and R.C Punnett and found that different varieties of chickens have different shapes of the comb. For example – Wyandottes have a “rose” comb and Brahmas have a “pea” comb. Punnett and Bateson crossed a Brahma chicken and a Wyandotte chicken, all the offspring produced in the ${\text{first filial (F}}_1\text{) generation}$ had a new form of comb which termed as “walnut” comb.

Explanation of Solution

A cross between $\text{RRPP (walnut) × rrpp (single)}$

$\begin{array}{l}\text{ Parents}\to \text{ RRPP × rrpp}\\ \text{ (walnut) (single)}\\ \downarrow \downarrow \\ \text{Gametes }\to \text{ RP rp}\\ \\ {\text{F}}_{\text{1}}\to \text{ RrPp (all walnut comb)}\\ \end{array}$

Hence, all the progeny produced by a cross between $\text{RRPP (walnut) × rrpp (single)}$

will have a walnut comb.

b.

Summary Introduction

To determine:

The progeny with the types of combs from the following cross $RrPp\times rrpp$

Introduction:

The different shapes of the comb in chicken are caused due to the interaction between two different genes. This study was conducted by William Bateson and R.C Punnett and found that different varieties of chickens have different shapes of the comb. For example – Wyandottes have a “rose” comb and Brahmas have a “pea” comb. Punnett and Bateson crossed a Brahma chicken and a Wyandotte chicken, all the offspring produced in the ${\text{first filial (F}}_1\text{) generation}$ had a new form of comb which termed as “walnut” comb.

Explanation of Solution

A cross between $\text{RrPp (walnut) × rrpp (single)}\text{.}$

$\begin{array}{l}\text{ Parents}\to \text{ RrPp × rrpp}\\ \text{ (walnut) (single)}\\ \downarrow \downarrow \\ \text{Gametes }\to \text{ RP, rp, rP, Rp }\times \text{ rp }\end{array}$

${\text{F}}_{\text{1}}\text{ generation:}$

	$rp$
$RP$	$\begin{array}{l}\text{ RrPp}\\ \text{ (walnut)}\end{array}$
$rp$	$\begin{array}{l}\text{ rrpp}\\ \text{ (single)}\end{array}$
$rP$	$\begin{array}{l}\text{ rrPp}\\ \text{ (pea)}\end{array}$
$Rp$	$\begin{array}{l}\text{ Rrpp}\\ \text{ (rose)}\end{array}$

Hence, the progeny produced are,¼ walnut, ¼ single, ¼ pea, and ¼ rose.

c.

Summary Introduction

To determine:

The progeny with the types of combs from the following cross $RrPp\times RrPp$

Introduction:

The different shapes of the comb in chicken are caused due to the interaction between two different genes. This study was conducted by William Bateson and R.C Punnett and found that different varieties of chickens have different shapes of the comb. For example – Wyandottes have a “rose” comb and Brahmas have a “pea” comb. Punnett and Bateson crossed a Brahma chicken and a Wyandotte chicken, all the offspring produced in the ${\text{first filial (F}}_1\text{) generation}$ had a new form of comb which termed as “walnut” comb.

Explanation of Solution

A cross between $\text{RrPp (walnut) × RrPp (walnut)}$

$\begin{array}{l}\text{ Parents}\to \text{ RrPp × RrPp}\\ \text{ (walnut) (walnut)}\\ \downarrow \downarrow \\ \text{Gametes }\to \text{RP, Rp, rP, rp }\times \text{ RP, Rp, rP, rp }\end{array}$

${\text{F}}_{\text{1}}\text{ generation:}$

	$RP$	$Rp$	$rP$	$rp$
$RP$	$\begin{array}{l}\text{ RRPP}\\ \text{ (walnut)}\end{array}$	$\begin{array}{l}\text{ RRPp}\\ \text{ (walnut)}\end{array}$	$\begin{array}{l}\text{ RrPP}\\ \text{ (walnut)}\end{array}$	$\begin{array}{l}\text{ RrPp}\\ \text{ (walnut)}\end{array}$
$Rp$	$\begin{array}{l}\text{ RRPp}\\ \text{ (walnut)}\end{array}$	$\begin{array}{l}\text{ RRpp}\\ \text{ (rose)}\end{array}$	$\begin{array}{l}\text{ RrPp}\\ \text{ (walnut)}\end{array}$	$\begin{array}{l}\text{ Rrpp}\\ \text{ (rose)}\end{array}$
$rP$	$\begin{array}{l}\text{ RrPP}\\ \text{ (walnut)}\end{array}$	$\begin{array}{l}\text{ RrPp}\\ \text{ (walnut)}\end{array}$	$\begin{array}{l}\text{ rrPP}\\ \text{ (pea)}\end{array}$	$\begin{array}{l}\text{ rrPp}\\ \text{ (pea)}\end{array}$
$rp$	$\begin{array}{l}\text{ RrPp}\\ \text{ (walnut)}\end{array}$	$\begin{array}{l}\text{ Rrpp}\\ \text{ (rose)}\end{array}$	$\begin{array}{l}\text{ rrPp}\\ \text{ (pea)}\end{array}$	$\begin{array}{l}\text{ rrpp}\\ \text{ (single)}\end{array}$

Hence, the progeny produced by this cross has a phenotypic ratio:

$\text{9 (walnut) : 3 (rose) : 3 (pea) : 1 (single)}\text{.}$

d.

Summary Introduction

To determine:

The progeny with the types of combs from the following cross $Rrpp\times Rrpp$

Introduction:

The different shapes of the comb in chicken are caused due to the interaction between two different genes. This study was conducted by William Bateson and R.C Punnett and found that different varieties of chickens have different shapes of the comb. For example – Wyandottes have a “rose” comb and Brahmas have a “pea” comb. Punnett and Bateson crossed a Brahma chicken and a Wyandotte chicken, all the offspring produced in the ${\text{first filial (F}}_1\text{) generation}$ had a new form of comb which termed as “walnut” comb.

Explanation of Solution

A cross between $\text{Rrpp (rose) × Rrpp (rose)}\text{.}$

$\begin{array}{l}\text{ Parents}\to \text{ Rrpp × Rrpp}\\ \text{ (rose) (rose)}\\ \downarrow \downarrow \\ \text{Gametes }\to \text{ Rp, rp }\times \text{ Rp, rp }\end{array}$

${\text{F}}_{\text{1}}\text{ generation:}$

	$Rp$	$rp$
$Rp$	$\begin{array}{l}\text{ RRpp}\\ \text{ (rose)}\end{array}$	$\begin{array}{l}\text{ Rrpp}\\ \text{ (rose)}\end{array}$
$rp$	$\begin{array}{l}\text{ Rrpp}\\ \text{ (rose)}\end{array}$	$\begin{array}{l}\text{ rrpp}\\ \text{ (single)}\end{array}$

Hence, the progeny produced by this cross will be in the phenotypic ratio of $\text{3 (rose) : 1 (single)}$.

e.

Summary Introduction

To determine:

The progeny with the types of combs from the following cross $Rrpp\times rrPp$

Introduction:

The different shapes of the comb in chicken are caused due to the interaction between two different genes. This study was conducted by William Bateson and R.C Punnett and found that different varieties of chickens have different shapes of the comb. For example – Wyandottes have a “rose” comb and Brahmas have a “pea” comb. Punnett and Bateson crossed a Brahma chicken and a Wyandotte chicken, all the offspring produced in the ${\text{first filial (F}}_1\text{) generation}$ had a new form of comb which termed as “walnut” comb.

Explanation of Solution

A cross between $\text{Rrpp (rose) × rrPp (pea)}\text{.}$

$\begin{array}{l}\text{ Parents}\to \text{ Rrpp × rrPp}\\ \text{ (rose) (pea))}\\ \downarrow \downarrow \\ \text{Gametes }\to \text{ Rp, rp }\times \text{ rP, rp }\end{array}$

${\text{F}}_{\text{1}}\text{ generation:}$

	$rP$	$rp$
$Rp$	$\begin{array}{l}\text{ RrPp}\\ \text{ (walnut)}\end{array}$	$\begin{array}{l}\text{ Rrpp}\\ \text{ (rose)}\end{array}$
$rp$	$\begin{array}{l}\text{ rrPp}\\ \text{ (pea)}\end{array}$	$\begin{array}{l}\text{ rrpp}\\ \text{ (single)}\end{array}$

Hence, the progeny produced by this cross will be in the phenotypic ratio of $\text{1 (walnut) : 1 (rose) : 1 (pea) : 1 (single) }$.

f.

Summary Introduction

To determine:

The progeny with the types of combs from the following cross $Rrpp\times rrpp$

Introduction:

The different shapes of the comb in chicken are caused due to the interaction between two different genes. This study was conducted by William Bateson and R.C Punnett and found that different varieties of chickens have different shapes of comb. For example – Wyandottes have a “rose” comb and Brahmas have a “pea” comb. Punnett and Bateson crossed a Brahma chicken and a Wyandotte chicken, all the offspring produced in the ${\text{first filial (F}}_1\text{) generation}$ had a new form of comb which termed as “walnut” comb.

Explanation of Solution

A cross between $\text{Rrpp (rose) × rrpp (single)}\text{.}$

$\begin{array}{l}\text{ Parents}\to \text{ Rrpp × rrpp}\\ \text{ (rose) (single)}\\ \downarrow \downarrow \\ \text{Gametes }\to \text{ Rp, rp }\times \text{ rp }\end{array}$

${\text{F}}_{\text{1}}\text{ generation:}$

	$rp$
$Rp$	$\begin{array}{l}\text{ Rrpp}\\ \text{ (rose)}\end{array}$
$rp$	$\begin{array}{l}\text{ rrpp}\\ \text{ (single)}\end{array}$

Hence, the progeny produced by this cross will be in the phenotypic ratio of $\text{ 1 (rose) : 1 (single) }$.