Gene recombination refers to the mixing of genes from different individuals that occurs during sexual reproduction.
Gene recombination is responsible for mixing between genes.
In eukaryotes, gene recombination occurs through two processes during meiosis: independent chromosome segregation and permutation (crossing over).
Many combinations can be formed between the mixing of genes from two individuals.
As an example, we have the mixture of maternal and paternal chromosomes: the number of possible combinations can be calculated by the expression 2no. (n=number of chromosome pairs in the individual).
So, the human species has 223, that is, 8,388,608 different combinations between the chromosomes of the father and the mother.
Types of Gene Recombination
Gene recombination can be homologous or non-homologous:
- Homologous gene recombination: occurs between identical or very similar DNA sequences. That is, between homologous sequences.
- Non-homologous gene recombination: occurs between DNA sequences without any similarity to each other.
Also know about the Meiosis.
Bacterial Genetic Recombination
Bacteria have two mechanisms of genetic variability: a mutation and gene recombination.
Gene recombination occurs by three types of mechanisms: transformation, conjugation and transduction.
THE transformation it is the incorporation of free DNA by the bacterial cell.
THE conjugation it is the process of transferring DNA from one bacterium to another, involving contact between two cells.
The process starts with the formation of a specific giver-receiver union. In a second phase, preparation for DNA transfer takes place. After DNA transfer, a functional replicative plasmid is formed in the recipient.
THE transduction it is the transfer of genetic material, between cells, mediated by bacteriophages.
Gene Recombination and Mutation
Gene recombination and mutation are different processes.
However, both processes are involved with the genetic variability of individuals.
The mutation corresponds to hereditary changes in the DNA sequence. It is the primary source of variability.
Gene recombination is the mixing of genes between individuals of the same species. It increases the variability primarily produced by the mutation.
Thus, it can be said that mutation and recombination work together. Meanwhile, the mutation modifies the DNA. Recombination promotes mixing of genes modified between two individuals.
Gene Recombination and Evolution
The modern theory of evolution (Neodarwinism) considers three main factors in the evolutionary process: gene mutation, gene recombination and natural selection.
Mutation and gene recombination are responsible for genetic variability, ensure that individuals are genetically different at each generation.
Without genetic variability processes such as gene recombination and mutation, evolution would be extremely slow. This is because there would be no mechanisms to bring together the mutations of different individuals.
It is through genetic variability that the evolution and adaptation of organisms to the environment occur.