Cutting the second slide & Dollo’s “Law”

A recent study on house dust mites has shown that the mighty mites have evolved “in reverse” from an obligate parasite into a free living organism. That is pretty cool. Yet, I find myself in the position once again of questioning the way the research is presented without questioning the quality of the research itself.

For permanent parasites and other symbionts, the most intriguing question is whether these organisms can return to a free-living lifestyle and, thus, escape an evolutionary “dead end.” This question is directly related to Dollo’s law, which stipulates that a complex trait (such as being free living vs. parasitic) cannot re-evolve again in the same form. Here, we present conclusive evidence that house dust mites, a group of medically important free-living organisms, evolved from permanent parasites of warm-blooded vertebrates. – Klimov & O’Connor 2013

The researchers present their result as a refutation of Dollo’s Law, which postulates that evolution is irreversible: Continue reading “Cutting the second slide & Dollo’s “Law””