Question

Brief About exchange of Genes Between Homologous Chromosomes

Answer 1

Hint: Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Homologous Chromosomes are the pair of chromosomes with the same sequence of genes.

Complete answer:
During synapsis in meiosis $$1$$ which means when the homologous chromosomes pair together during the prophase $$1$$, is when crossing over occurs, and the chromatids of the homologous pairs cross over and swap genetic material.

Both arms of homologous chromosomes and centromeric position are the same. Alleles are of the same genes which are present in that same loci. The pairing of homologous chromosomes is brought about in meiosis $$1$$.

The exchange of genes between the two homologous chromosomes is known as chromosomal crossover. This exchange between non-sister chromatids results in the production of recombinant chromosomes during sexual reproduction. It is known to be one of the final stages of genetic recombination, it takes place in the pachytene stage of prophase $$1$$ of meiosis during the phenomena of synapsis. The crossing occurs when the matching areas on the matching chromosomes disconnect to reconnect to other chromosomes.

Recombination is the process of the exchange of genetic information between two chromosomes or between two parts of the same chromosome. Recombination is mainly of four types:
i) Homologous recombination occurs during meiosis when a part of the chromosome is exchanged between two homologous chromosomes.
ii) Non-homologous recombination is the exchange of genetic information between dissimilar chromosomes.
iii) Site-specific recombination is used in recombinant technology, DNA is cut at a specific site using restriction enzymes and a new piece of DNA is inserted.
iv) In replicative recombination, a new copy of a transposable element is generated at a new site in the same chromosome.

Note: The process of crossing over leads to the process called as recombination of alleles between non-sister chromatids of homologous chromosomes. During the process of meiosis, crossing over is followed by recombination. Crossing over is the exchange of genetic material between homologous chromosomes and thereby leading to recombination.