The dodo bird (Raphus cucullatus) lived on the Mauritius Islands until the arrival of European sailors, who quickly hunted the large, placid, flightless bird to extinction. Rapid morphological evolution such as often accompanies island isolation had caused the bird's huge size and obscured its physical resemblance to any near relatives. However, sequencing of mitochondrial DNA from dodo bones reveals that they were pigeons, closely related to the Nicobar pigeon from other islands in the Indian Ocean. Why was mitochondrial DNA suited to the study of this extinct species?

Key Concepts

Mitochondrial DNA (mtDNA)

Mitochondrial DNA is a type of genetic material found in the mitochondria, the energy-producing structures within cells. Unlike nuclear DNA, mtDNA is inherited maternally and has a higher mutation rate, making it useful for studying evolutionary relationships and tracing lineage. Its relatively small size and abundance in cells also facilitate the extraction and analysis of genetic information, especially from ancient or degraded samples.

Phylogenetics

Phylogenetics is the study of evolutionary relationships among biological species based on genetic information. By comparing mtDNA sequences from different species, scientists can construct phylogenetic trees that illustrate how closely related species are to one another. This method helps in understanding the evolutionary history and divergence of species, such as the dodo bird and its relatives.

Extinction and Conservation Genetics

Extinction refers to the complete loss of a species, often due to human activities or environmental changes. Conservation genetics uses genetic data to understand the genetic diversity and health of endangered species, which can inform conservation efforts. Studying the genetics of extinct species like the dodo can provide insights into their evolutionary history and inform strategies to protect closely related species that are still extant.