Gene Duplication and Evolution:
- In 1970, biologist Susumu Ohno proposed that gene duplication is a key mechanism for creating new genes.
- When genes are duplicated, one copy maintains the original function, while the other is free to mutate and potentially gain new functions.
- A key challenge to this theory was the problem of protein over-production from duplicated genes, which can lead to diseases.
Relevance : GS 3(Science )
Recent Research on Gene Duplication:
- University of Nevada, Reno: Researchers found that the promoters of duplicated genes have more methylated DNA than non-duplicated genes.
- Methylation helps prevent over-expression of proteins, reducing harmful effects of duplication and enabling the new gene to survive and evolve.
- This process also increases mutation rates, contributing to gene evolution.
Exogenous DNA and Incipient Genes:
- Max Planck Institute Study: Researchers inserted random DNA sequences into human cells, creating proteins and observing their effects on cell growth.
- Over time, they found that 40% of the new DNA sequences influenced cell growth, behaving like incipient genes that could become relevant for evolution.
Gene Retention in Evolution:
- For a gene to be retained in a genome, it must serve a functional purpose or be allowed to mutate beneficially.
- An example of gene retention is the ABO blood group system, where different variants (A, B, O) have persisted across species, even though some variants don’t seem to be essential.
Key Concepts of Gene Function and Structure:
- The human genome contains 20,000 protein-coding genes and 20,000 genes responsible for creating RNA that regulates other genes.
- Promoters and enhancers play a crucial role in determining when and where genes are transcribed into mRNA for protein production.
- The human genome consists of 24 chromosomes, with males having one X and one Y chromosome, and females having two X chromosomes.
Implications for Evolutionary Biology:
- These studies highlight the complexity of gene creation, duplication, and evolution, offering new perspectives on how new genes arise and are preserved over time.
- Random DNA insertions can have evolutionary significance, contributing to the adaptation of organisms.
