Relationship Between Crossing Over and Genetic Variation

A) Crossing over decreases genetic variation.

B) Crossing over increases genetic variation.

C) Crossing over has no effect on genetic variation.

D) The relationship between crossing over and genetic variation is unpredictable.

Correct Answer: B) Crossing over increases genetic variation.

Explanation:

Crossing over, also known as recombination, is the exchange of genetic material between homologous chromosomes during meiosis. This process occurs when the chromatids of paired homologous chromosomes cross over one another and exchange genetic material. Crossing over plays a significant role in generating genetic variation in offspring.

During meiosis, the process of crossing over shuffles the genetic information from each parent, creating new combinations of alleles. This recombination of genetic material can lead to the creation of new alleles and genetic variations in the offspring that were not present in the parents. Therefore, crossing over increases genetic variation in the offspring.

To better understand the relationship between crossing over and genetic variation, let's consider an example. Suppose two individuals, one with blue eyes (BB) and the other with brown eyes (bb), mate to produce offspring. Each parent has two alleles for the eye color gene, one inherited from each parent.

During meiosis, the homologous chromosomes align and crossover, resulting in the exchange of genetic material. As a result, the offspring can inherit different combinations of alleles. For instance, one offspring could inherit the B allele from the blue-eyed parent and the b allele from the brown-eyed parent, resulting in a genotype of Bb, and have hazel eyes. Another offspring could inherit the BB allele from the blue-eyed parent and the bb allele from the brown-eyed parent, resulting in a genotype of Bb, and have blue eyes. Therefore, crossing over has led to genetic variation in the offspring.

In conclusion, crossing over plays a crucial role in creating genetic variation in offspring by shuffling the genetic information from each parent and generating new combinations of alleles. As a result, crossing over increases genetic variation in the offspring.