An Academia Sinica research group recently overturned a three-centuries-old belief after discovering that Stylophora pistillata, a widely used “laboratory rat” for coral research, encompasses multiple subspecies rather than being just a single variant.
Led by Academia Sinica’s Biodiversity Research Center fellow Chaolun Allen Chen (陳昭倫), the research team found that Stylophora pistillata consists of at least four distinctive sub-types, with each having different levels of tolerance toward temperature and sunlight, overturning the long-standing belief, held since the 18th century, that Stylophora pistillata found worldwide belonged to one genetically homogeneous species.
The team, consisting of several marine biologists from Taiwan and abroad, reached the conclusion after using DNA barcoding to analyze mitochondrial cytochrome oxidase I (COI) gene sequences from 241 coral colonies collected from 34 locations across four marine areas, including the Western Pacific Ocean, the Indian Ocean, the Red Sea and the Persian Gulf.
The results of the study, which was subsidized by the National Science Council, have been published on the Scientific Reports Web site, a research journal from the publishers of Nature, on March 22.
According to Chen, S pistillata is a widely distributed coral species commonly used in scientific studies, but his research found that samples of the coral found in different areas showed different tolerances for a range of environmental factors.
“For instance, S pistillata samples collected from the Persian Gulf exhibit higher levels of heat tolerance than their Pacific Ocean counterparts,” Chen said, adding that the practice of conserving coral through assisted migration might result in biological invasions.
Chen said that as the four variants of S pistillata could have diverged from one another as long ago as 50 million years, past research on the species might also require re-examination.
Recalling the preparatory period for the six-year research project, Chen said that in an effort to collect coral samples from different habitats, he even traveled to Somalia, where piracy is prevalent.
“I had to be properly armed and escorted by US vessels before I could sail out to collect coral samples. Prior to that, I also had to go through the red tape to have access to species that are not only strictly protected, but also of high economic value,” Chen said.
“We could not have completed the project without going through the disappointments and hardships that we did,” Chen added.
Saying that DNA barcoding had been used to differentiate between closely related species and identify new ones, Chen added that the techniques could also be employed in border inspections in the future once an electronic database of DNA barcodes for various species has been established.
“By that time, customs officers could identify any smuggled species simply via a palm-sized device,” Chen said.