Question

Genetic recombination plays a role in both maintenance and diversity within an organism. Explain how this balance is achieved and the underlying mechanism of recombination that are involved.

Answer 1

Genetic recombination balances genetic stability and diversity through mechanisms like chromosomal crossover, independent assortment during meiosis, and mutations which introduce new alleles into a population.

Step-by-step explanation:

Genetic recombination serves as a critical function in the maintenance of genetic stability and the introduction of genetic diversity. The balance is achieved through mechanisms such as chromosomal crossover during meiosis, the random assortment of chromosomes, and mutations. In meiosis, specifically during prophase I, homologous chromosomes undergo crossing over, which is the exchange of genetic material between nonsister chromatids. This creates new combinations of alleles on the chromosomes that are segregated into the gametes.

Moreover, during metaphase I, the random alignment of chromosomes leads to independent assortment, further contributing to genetic variation. Mutations, which are changes in the DNA sequence, also introduce new alleles into a population, affecting traits in various ways ranging from deleterious to beneficial or having no effect at all.

Answer 2

Crossing-over between homologous chromosomes (prophase 1), the random lining of homologous chromosomes (metaphase 1), and random fertilization are the mechanisms involved in genetic variation.

Step-by-step explanation:

Crossing-over between homologous chromosomes (prophase 1), the random lining of homologous chromosomes (metaphase 1), and random fertilization are the mechanisms involved in genetic variation.

The Crossing-over events occur between two homologous chromosomes in the equatorial plane and make the daughter cells genetically different from the original one. The Chiasma is the position where two homologous chromatids interchange genetic information, giving a place for new genetic material or information to be provided to descendants. After crossing over, homologous chromosomes get separated again.

On the equatorial plane, homologous paired together, randomly aline with their kinetochores facing opposite poles. The random arrangement of tetrads is different in every cell going through the meiosis process. There is no equal alinement between two cells. When tetrads aline in the equatorial plane, there is no predetermined order for each of the homologous chromosomes of each tetrad to face one of the poles and then migrate to it while separating. Chromosomes of the homologous pair arrange to face any of the poles to migrate forward to it. Each of the chromosomes has two possibilities for orientation at the plane. When the new haploid cells are formed, the number of variations in each cell is also different and depends on the chromosomes that form that cell. The order in the equatorial plane is what introduces variation into the gametes, being almost impossible for two gametes to have the same genetic charge.

Independent assortment occurs when the alleles from two or more different genes distribute in gametes independently from each other. In other words, a gamete receives an allele from a gene that does not depend on nor influence the allele of another gene in the same gamete. This can only be applied to independent genes. An organism gets only one of the members of the chromatids pair of each parent.