Mitogenomics is the the the sequencing and analysis of mitochondrial DNA. The majority of mitochondrial DNA comes from maternal descent, is relatively small, and has a high nucleotide substitution mutation rate. allowing researchers to better understand the evolutionary history and phylogenetic relationships of a particular organism.
Sun et al. use this technique to study the geographic origin and relationships between shallow water and deep-sea Asteroidea. For their experiment, they selected five deep-sea genomes. It showed that deep-sea Asteroidea had a much higher A+T nucleotide content compared to those in shallow water, providing insight into the divergence of base composition. Studying the genome also allowed researchers to identify the sequences responsible for the deep-sea adaptations against cold temperatures and hydrostatic pressure.
By comparing sequences of different Asteroidea with each other and seeing when new mutations arose and for how long they were passed on, the origin of each mutation could be speculated. The more matches in DNA, the closer the relationship. Using this information, it was speculated that during the Triassic-Jurassic transition marked by a mass extinction event, the rapid divergence between the deep and shallow water varieties occurred to fill in the newly opened niches. Although it was inconclusive, the results also pointed towards a deep-sea ancestral origin.
It is important to understand the evolutionary history and evolutionary mechanisms of organisms since it helps us understand why a species may exist in a certain environment and how the world as we know it today came to be. It is also important to compare the survival mechanisms of different organisms because it can help with cultivation for commercial purposes or conservation efforts.
What to read next: Global Diversity and Phylogeny of the Asteroidea (Echinodermata)