molecular evolution

Molecular evolution is the study of evolutionary changes at the molecular level, focusing on changes in DNA and protein sequences over time. These changes, or mutations, are the primary source of genetic variation, which is the raw material for evolution.1234

Key concepts include:
* Mutations: Alterations in the genetic material (DNA or RNA) that can be passed to descendants. These can be gene mutations (point mutations) or chromosomal mutations.34
* Genetic Drift: Random changes in allele frequencies within a population, particularly significant in smaller populations.56
* Neutrality Theory: Proposes that many molecular changes are selectively neutral, meaning they are due to genetic drift rather than natural selection.5
* Molecular Clock: The idea that macromolecules like DNA and proteins evolve at a relatively constant rate, allowing scientists to estimate divergence times between species based on the number of molecular differences.72

Proteins like cytochrome c and fibrinopeptides, as well as DNA sequences, store evolutionary information and can be used to reconstruct evolutionary histories and relationships between organisms.17