"We caution researchers..."

Even in the rather young discipline of DNA Barcoding history seems to repeat itself. About six years ago researchers had a closer look at some leech species of the genus Helobdella that had been workhorses of annelid developmental biology for decades. Helobdella robusta is a widely used model organism and its genome was sequenced recently. However, the study revealed that, collectively, the Helobdella development community had been working on five distinct species. As a consequence the authors stated:

We caution researchers similarly working on multiple wild-collected isolates to preserve voucher specimens and to obtain from these a molecular "barcode," such as a COI gene sequence, to reveal genetic variation in animals used for research.

A bit over a week ago an international group of researchers published a study with a similar approach. The species they were interested in was Stylophora pistillata a widely used coral species with highly variable morphology and a broad biogeographic range (Red Sea to western central Pacific). They showed that this species in fact comprises four deeply divergent clades corresponding to different geographical regions. Furthermore on the basis of the fossil record of Stylophora, they estimated that these four clades diverged from one another 52-30 Million years ago and propose to recognize them as four distinct species.

These findings have broad implications for comparative ecological and/or physiological studies carried out using Stylophora pistillata as a model species, and highlight the fact that phenotypic plasticity, thought to be common in scleractinian corals, can mask significant genetic variation.

Another good reason to have a closer look at genetic variation in species used as model organisms in research.