Gene, Genetic Maps, Genetic Exchange

A gene is an elementary and structural unit of heredity. The concept of the gene was proposed by Gregor Mendel, who conducted experiments on crossing peas and discovered that some traits are transmitted discretely to offspring. Later it was shown that genes are localized on chromosomes. Modern research has revealed the molecular nature of the gene - it is a section of a DNA molecule that encodes a protein or RNA.

Genetic maps are graphical displays of the location of genes on chromosomes. The order of genes and the distances between them are determined using crossover frequency analysis. The further apart genes are located on a chromosome, the higher the likelihood of crossing over between them. Thus, knowing the recombination frequencies, it is possible to construct an approximate genetic map.

Genetic exchange is the transfer of genetic material between organisms or cells. The main methods of gene exchange:

1. Crossing over is the exchange of sections between homologous chromosomes during the process of meiosis. Leads to gene recombination.

2. Conjugation is the transfer of genetic material from a donor cell to a recipient cell in bacteria.

3. Transduction is the transfer of bacterial genes using viruses (bacteriophages).

4. Transformation is the absorption of naked DNA by a bacterial cell from the environment.

The exchange of genetic material plays an important role in evolution, increasing the genetic diversity of populations.