Chapter 10, Problem 31A

Summary Introduction

To hypothesize:

The reason that reduced genetic recombination is advantageous to some sexually reproducing organisms

Introduction:

The main advantage of sexual reproduction is that it produces genetic variation in species. Genetic variation arises due to differences in genetic sequence in DNA among individuals. Genetic variation helps species survive better in adverse conditions. Meiosis contributes to the amount of genetic recombination in a particular species.

Answer to Problem 31A

Genetic variation is possible during crossing over and fertilization when gametes randomly combine. This changes the gene pool in a population. Yet there are some sexually reproducing organisms that do not seem to display recombination mechanism. These organisms seem to be well established in their niches and are in stable environments. They do not need natural selection of the variations to occur. If the population of organisms is well settled in its natural environment, it might benefit by actually avoiding recombination mechanism.

Explanation of Solution

Genetic variation can be increased by the following processes:

1. Crossing over
2. Random mating
3. Independent assortment

Variation helps a population to adapt to its changing environment. Variations increase the organism’s ability to survive and reproduce which in turn leads the survival of alleles in the population. If a population is already well settled in its environment, it might not need variations to occur. Such organisms tend to avoid genetic recombination through sexual reproduction. If the organisms are stable in their niches they do not need recombination mechanism.