Chapter 8.2, Problem 20AQP

a.

Summary Introduction

To explain:

The type of chromosome mutations required to change the chromosome $\text{AB•CDEFG}$ into $\text{ABAB•CDEFG}$.

Introduction:

Chromosomal rearrangements are the mutations in chromosomes that alter the structures of individual chromosomes. The four types of chromosomal rearrangements are deletions, duplications, translocations, and inversions.

Explanation of Solution

Duplication is a type of mutation, which results in the duplication or doubling of some part of the chromosome. For the conversion of $\text{AB•CDEFG}$ into $\text{ABAB•CDEFG}$, duplication of AB genes is required. The duplicated alleles lie next to original alleles.

b.

Summary Introduction

To explain:

The type of chromosome mutations required to change the chromosome $\text{AB•CDEFG}$ into $\text{AB•CDEABFG}$.

Introduction:

Chromosomal rearrangements are the mutations in chromosomes that alter the structures of individual chromosomes. The four types of chromosomal rearrangements are deletions, duplications, translocations, and inversions.

Explanation of Solution

Duplication is a type of mutation which results in duplication or doubling of some part of the chromosome. For the conversion of $\text{AB•CDEFG}$ into $\text{AB•CDEABFG}$, displaced duplication of AB between E and F is required. In displaced duplication, the duplicated alleles lie far away from the original alleles.

c.

Summary Introduction

To explain:

The type of chromosome mutations required to change the chromosome $\text{AB•CDEFG}$ into $\text{AB•CFEDG}$.

Introduction:

Chromosomal rearrangements are the mutations in chromosomes that alter the structures of individual chromosomes. The four types of chromosomal rearrangements are deletions, duplications, translocations, and inversions.

Explanation of Solution

Inversion is a type of chromosomal rearrangement mutation which involves inversion of a segment of chromosome to $180°$. For the conversion of $\text{AB•CDEFG}$ into $\text{AB•CFEDG}$ paracentric inversion is required. Paracentric inversion does not involve centromeres. The genes DEF have been inverted.

d.

Summary Introduction

To explain:

The type of chromosome mutations required to change the chromosome $\text{AB•CDEFG}$ into $\text{A•CDEFG}$.

Introduction:

Chromosomal rearrangements are the mutations in chromosomes that alter the structures of individual chromosomes. The four types of chromosomal rearrangements are deletions, duplications, translocations, and inversions.

Explanation of Solution

In deletion mutation, some part of the chromosome gets deleted which results in shortening of chromosome. For the conversion of $\text{AB•CDEFG}$ into $\text{A•CDEFG}$, deletion of B gene is required.

e.

Summary Introduction

To explain:

The type of chromosome mutations required to change the chromosome $\text{AB•CDEFG}$ into $\text{AB•CDE}$.

Introduction:

Chromosomal rearrangements are the mutations in chromosomes that alter the structures of individual chromosomes. The four types of chromosomal rearrangements are deletions, duplications, translocations, and inversions.

Explanation of Solution

In deletion mutation, some part of the chromosome gets deleted which results in shortening of chromosome. For the conversion of $\text{AB•CDEFG}$ into $\text{AB•CDE}$, FG genes need to be deleted.

f.

Summary Introduction

To explain:

The type of chromosome mutations required to change the chromosome $\text{AB•CDEFG}$ into $\text{AB•EDCFG}$.

Introduction:

Chromosomal rearrangements are the mutations in chromosomes that alter the structures of individual chromosomes. The four types of chromosomal rearrangements are deletions, duplications, translocations, and inversions.

Explanation of Solution

The inversion mutation involves inversion of a segment of chromosome to $180°$ takes place. For the conversion of $\text{AB•CDEFG}$ into $\text{AB•EDCFG}$, paracentric inversion is required. In this case, the CDE genes have inverted. As the centromere is not involved, it can be converted through paracentric inversion.

g.

Summary Introduction

To explain:

The type of chromosome mutations required to change the chromosome $\text{AB•CDEFG}$ into $\text{C•BADEFG}$.

Introduction:

Chromosomal rearrangements are the mutations in chromosomes that alter the structures of individual chromosomes. The four types of chromosomal rearrangements are deletions, duplications, translocations, and inversions.

Explanation of Solution

The inversion mutation involves inversion of a segment of chromosome to $180°$ takes place. For the conversion of $\text{AB•CDEFG}$ into $\text{C•BADEFG}$, pericentric inversion is required. The genes ABC are inverted. Since inversion also involves centromere, it is pericentric inversion.

h.

Summary Introduction

To explain:

The type of chromosome mutations required to change the chromosome $\text{AB•CDEFG}$ into $\text{AB•CFEDFEDG}$.

Introduction:

Chromosomal rearrangements are the mutations in chromosomes that alter the structures of individual chromosomes. The four types of chromosomal rearrangements are deletions, duplications, translocations, and inversions.

Explanation of Solution

For the conversion of $\text{AB•CDEFG}$ into $\text{AB•CFEDFEDG}$, inversion and duplication is required. The genes DEF is inverted and then duplicated. Both the original sequence and new sequence are lie side by side.

i.

Summary Introduction

To explain:

The type of chromosome mutations required to change the chromosome $\text{AB•CDEFG}$ into $\text{AB•CDEFCDFEG}$.

Introduction:

Chromosomal rearrangements are the mutations in chromosomes that alter the structures of individual chromosomes. The four types of chromosomal rearrangements are deletions, duplications, translocations, and inversions.

Explanation of Solution

For the conversion of $\text{AB•CDEFG}$ into $\text{AB•CDEFCDFEG}$ duplication and inversion is required. Genes CDEF has duplicated and in the duplicated sequence, gene EF is inverted.

Conclusion

Chromosomal rearrangements include deletion, inversion, duplication, and translocation. For the conversion of segment of chromosome into another, one or more than one type of chromosomal rearrangement takes place.