Gene duplication

Gene Duplication

Gene duplication process

Gene duplication is a major mechanism through which new genetic material is generated during molecular evolution. As a result of gene duplication, multiple copies of a gene can exist within an organism's genome. This process can lead to genetic diversity and the evolution of new functions.

Mechanisms of Gene Duplication

Gene duplication can occur through several mechanisms:

• Unequal crossing over: During meiosis, homologous chromosomes may misalign, leading to unequal crossing over. This can result in one chromosome with a duplication and another with a deletion.

• Retrotransposition: A gene can be copied from RNA back into DNA and inserted into a new location in the genome. This process is mediated by retrotransposons.

• Segmental duplications: Large segments of DNA, often containing multiple genes, can be duplicated. These duplications can occur through mechanisms such as replication slippage or non-allelic homologous recombination.

Evolutionary Fate of Duplicate Genes

Evolutionary fate of duplicate genes

Once a gene is duplicated, the duplicate copies can undergo several evolutionary fates:

• Nonfunctionalization: One copy of the gene may accumulate deleterious mutations and become a pseudogene, losing its function.

• Neofunctionalization: One copy may acquire beneficial mutations that confer a new function, allowing the organism to adapt to new environments or challenges.

• Subfunctionalization: The original function of the gene may be divided between the two copies, with each copy specializing in part of the original function.

Importance in Evolution

Gene duplication is a crucial driver of evolutionary innovation. It provides raw material for the development of new genes and functions. Many important gene families, such as the globin family and the Hox genes, have arisen through gene duplication events.

Human Genome and Gene Duplication

Human karyotype

In the human genome, gene duplication has played a significant role in shaping our genetic landscape. Duplications can lead to genetic disorders if they disrupt normal gene function, but they can also contribute to genetic diversity and adaptation.

Related Pages

• Gene family
• Pseudogene
• Molecular evolution
• Chromosomal duplication