A comparison of the genomes of two species of coral demonstrates unexpected genetic diversity.
The first comparative genome study between two corals reveals significant evolutionary differences. These findings could help scientists understand the resilience of corals and how they might respond to climate change.
Reef-building corals diverged into two genetically distinct groups, called the robust clade and the complex clade, at least 240 million years ago. Until now, the only complex coral genome available has been for the complex coral Acropora digitifera. An international team, led by Christian Voolstra and Manuel Aranda from KAUST, sequenced the genome of the robust coral Stylophora pistillata and then compared it with the existing Acropora genome.
“Before we began sequencing, we had to develop a method to obtain Stylophora DNA that was not contaminated by DNA from the coral’s symbiotic algae,” says Aranda. “We removed the symbionts by isolating the coral nuclei before extracting the DNA.”
Corals exhibit high levels of genetic variation within the same species. This makes it even more difficult to stitch the genome together from the fragmented pieces of DNA.
“Once you have sequenced your genome, you must pick out and label each individual gene,” says Voolstra. “It’s like trying to read a book with no spaces between the words!”