Gene Duplication and Evolution

Introduction

• Gene duplication is a crucial mechanism in evolution that has contributed to the diversity of life on Earth.
• It involves the creation of extra copies of genes within an organism's genome.

Types of Gene Duplication

• Tandem Duplication: The duplicated genes are adjacent to each other on the chromosome.
• Segmental Duplication: Large segments of the chromosome containing multiple genes are duplicated.
• Whole-Genome Duplication (Polyploidy): Entire sets of chromosomes are duplicated, leading to multiple copies of all genes.

Importance of Gene Duplication in Evolution

• Gene duplication provides raw genetic material for evolutionary innovation.
• It allows for the divergence of duplicated genes into different functions over time.

Functional Divergence

• After duplication, the duplicated genes can accumulate mutations independently.
• Mutations may lead to changes in gene function, such as acquiring new roles or specialisations.
• Some duplicated genes may become non-functional pseudogenes.

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Gene Duplication and Evolution

Neofunctionalisation

• In some cases, one copy of a duplicated gene may acquire a completely new function.
• This can result in the evolution of novel traits or functions.
• Neofunctionalisation is a key driver of evolutionary innovation.

Subfunctionalisation

• In subfunctionalisation, each duplicate retains a subset of the original gene's functions.
• This can increase the efficiency of specific processes, contributing to an organism's adaptation.

Gene Family

• Gene duplication can lead to the formation of gene families.
• Gene families consist of related genes with similar sequences that perform various functions.

Examples of Gene Duplication in Evolution

• Haemoglobin Genes: In humans, there are multiple copies of haemoglobin genes that have evolved to function differently during different stages of life.
• Opsin Genes: Opsin genes in vertebrates have duplicated and diversified to enable the detection of various wavelengths of light, leading to colour vision.

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Gene Duplication and Evolution

Summary

Gene duplication is a fundamental process in evolution that results in the creation of extra gene copies within an organism's genome. It provides raw genetic material for evolutionary innovation and can lead to the divergence of duplicated genes into different functions. Functional divergence, neofunctionalisation, and subfunctionalisation are mechanisms that drive the evolution of duplicated genes, contributing to the diversity of life on Earth. Gene duplication can lead to the formation of gene families, and examples of its importance can be seen in genes such as haemoglobin and opsins in vertebrates.