Neofunctionalization

File:Antarctic Zoarcid Fish.jpg

Neofunctionalization is an evolutionary process by which a gene acquires a new function after a gene duplication event. This process is a significant mechanism in the evolution of new gene functions and contributes to the complexity and diversity of genomes.

Overview

Neofunctionalization occurs when one copy of a duplicated gene retains its original function, while the other copy accumulates mutations that lead to a new function. This process is contrasted with subfunctionalization, where both copies of the gene partition the original function between them.

Mechanism

The process of neofunctionalization begins with a gene duplication event, which can occur through various mechanisms such as unequal crossing over, retrotransposition, or whole genome duplication. Following duplication, one copy of the gene is free from selective pressure to maintain its original function, allowing it to accumulate mutations. Over time, these mutations can result in a new function for the gene, which can be beneficial to the organism.

Examples

One classic example of neofunctionalization is the evolution of the antifreeze proteins in Antarctic fish. These proteins evolved from a duplicated copy of a trypsinogen gene and acquired the new function of preventing ice crystal formation in the blood, which is crucial for survival in freezing temperatures.

Another example is the evolution of the globin gene family. The duplication and subsequent neofunctionalization of these genes have led to the development of different globin proteins, such as hemoglobin and myoglobin, each with distinct functions in oxygen transport and storage.

Significance

Neofunctionalization plays a critical role in the evolution of new biological functions and the adaptation of organisms to new environments. It contributes to the diversity of gene functions within a genome and can lead to the development of novel traits that provide a selective advantage.

Related Concepts

• Gene duplication
• Subfunctionalization
• Pseudogenization
• Evolutionary biology
• Molecular evolution

See Also

• Gene family
• Adaptive evolution
• Functional genomics