Question

Gene Duplication and Evolution Suppose that a rare DNA replication error results in the duplication of a single gene, giving the daughter cell two copies of the same gene. a. How does this change favor the acquisition of a new function by the daughter cell? b. In the vascular plant Arabidopsis thaliana, $50\mathrm{\%}$ to $60\mathrm{\%}$ of the genome consists of duplicate content. How might this confer a selective advantage?

Short answer

Gene duplication allows one copy to acquire new functions while retaining the original function, enhancing adaptability and offering evolutionary advantage.

Step-by-step solution

Understanding Gene Duplication

Gene duplication occurs due to errors in DNA replication, producing an extra copy of a gene. This is a common source of genetic variation.

Potential for New Function Acquisition

When a gene is duplicated, one copy can continue to perform the original function, allowing the second copy to evolve without the risk of losing the original function. This evolution can lead to new functions, giving the organism a potential adaptive advantage.

Example with Arabidopsis thaliana

In Arabidopsis thaliana, a significant proportion of its genome consists of duplicate genes. This genetic redundancy can provide the plant with robustness against genetic mutations and more chances for evolution through both genetic divergence and novel function acquisition.

Selective Advantage of Gene Duplication

Duplication provides a selective advantage by increasing genetic diversity and adaptability. This flexibility allows the organism better to withstand environmental changes and increases its evolutionary potential.

Key concepts

Evolutionary Biology

Evolutionary biology explores how organisms evolve over time through processes like natural selection and genetic variation. Gene duplication is a crucial mechanism in this field. It offers organisms new opportunities to adapt by creating additional genetic material. This increased genetic diversity can drive evolution by facilitating the emergence of new traits or functions.

With gene duplication, one copy of the gene can maintain its original role, while the other can mutate and potentially acquire new characteristics. Over many generations, this process can lead to significant evolutionary changes, providing insight into how complex life forms have developed. Thus, understanding gene duplication is essential for unraveling the complexities of evolutionary biology.

Genetic Variation

Genetic variation is the backbone of evolution, and it is what allows populations of organisms to adapt and survive changing environments. Gene duplication is a major source of this variation. It introduces new genetic material on which natural selection can act.

When a gene duplicates, the additional copy is free to undergo mutations without affecting the organism's functionality. This can lead to new traits that may be beneficial or neutral. However, some of these traits may confer advantages that help the organism thrive better in its environment, thereby becoming more prevalent in the population over generations.

Arabidopsis thaliana

Arabidopsis thaliana is a small flowering plant that is widely used as a model organism in plant biology. Its genome is notably rich in duplicate genes, making it an excellent subject for studying the impacts of gene duplication on evolution and adaptation.

Due to its simple genetic makeup and fast growth cycle, researchers can observe how genetic redundancy in Arabidopsis allows for increased robustness to mutations. Duplicate genes provide a buffer against harmful mutations, ensuring that functional traits are retained while allowing room for evolutionary innovation. The large proportion of duplicate genes in Arabidopsis thaliana demonstrates how gene duplication can support a species' adaptability and resilience.

Selective Advantage

A selective advantage occurs when specific traits increase an organism's chances of survival and reproduction within its environment. Gene duplication provides a selective advantage by enhancing genetic diversity and adaptability.

With duplicate genes, organisms can explore new evolutionary pathways without compromising existing functions. For instance, if environmental conditions change, the presence of additional gene copies may allow some individuals to survive when others cannot. This adaptability increases the likelihood of future generations possessing beneficial traits, which can eventually lead to widespread evolutionary changes.

• Increased genetic diversity due to duplication allows for greater environmental adaptability.
• It offers more opportunities for new traits that may prove beneficial under changing conditions.
• Duplicate genes can become specialized, enhancing specific adaptive traits.

By studying the dynamics of gene duplication, we can better understand how selective advantages contribute to the success of organisms in diverse ecological niches.