Animals that seem identical may be completely different species

Apr 22, 2009
This is the Lumbriculus variegatus worm. Credit: Image: Biopix

Animals that seem identical may belong to completely different species. This is the conclusion of researchers at the University of Gothenburg, Sweden, who have used DNA analyses to discover that one of our most common segmented worms is actually two types of worm. The result is one of many suggesting that the variety of species on the earth could be considerably larger than we thought.

"We could be talking about a large number of species that have existed undiscovered because they resemble other known species," says Professor Christer Erséus.

The segmented that were studied by Christer Erséus, doctoral student Daniel Gustavsson and their American colleague, are identical in appearance. From the very first time that they were described, they have been treated as the same species, and they are also found together in freshwater environments in North America, Sweden and the rest of Europe.

But when the researchers examined the worms using advanced methods for DNA analysis, they discovered that they were in fact two different species. Both species of worm differ in one of the examined genes by 17 percent, which is twice as much as the equivalent difference between humans and chimpanzees.

The research results, which are being published in the journal Molecular Phylogenetics and Evolution, could have major consequences. For example, the worms are frequently used for laboratory testing around the world, to examine the effects of environmental toxins.

"Different species have different characteristics. If it emerged that these two species differ in terms of their tolerance towards certain toxins, then it could be difficult to make comparisons between different studies," says Christer Erséus.

And as this advanced DNA technology is tested increasingly within various animal groups, it could, according to Christer Erséus, mean that our perception of the earth's biodiversity may need to be revised.
"There could be ten times as many species in total, compared with what we previously thought," he says.

The new of worm has not yet been given a name, since researchers have not yet decided which of the two will keep the old name, Lumbriculus variegatus.

Source: University of Gothenburg (news : web)

Explore further: A mathematical theory proposed by Alan Turing in 1952 can explain the formation of fingers

add to favorites email to friend print save as pdf

Related Stories

Zombie worms found in Britain's North Sea

Oct 19, 2005

So-called zombie worms that feed on bones of dead whales have reportedly been found in England's North Sea. Scientists say the worms belong to a new class of marine organism that scavenges whale carcasses, The Independent rep ...

Humans and chimpanzees, how similar are we?

Nov 20, 2006

The DNA sequences of humans and chimpanzees are 98.5 percent identical, but now Uppsala University researchers can show that parts of the genetic material are missing in one species or the other.

Slow human evolution revealed by worm genome

Jan 09, 2006

Humans have retained genomic characteristics of a very ancient ancestor that have been lost in simpler animals such as the fly, indicating that humans are one of the most slowly evolving species. This is the ...

Scientists uncover new dolphin species in Australian waters

Nov 21, 2008

(PhysOrg.com) -- Marine mammal experts have uncovered a new species of dolphin in Australian waters, challenging existing knowledge about bottlenose dolphin classifications and highlighting the country's marine biodiversity.

Scientist explores secrets to life through worms

Oct 17, 2008

Who would have thought that worms found in your composter - only seen with a microscope - could be used to study genetic disorders in humans? With 700 million years of separation and roughly half of its genes ...

Recommended for you

Invasive lionfish likely safe to eat after all

2 hours ago

Scientists have learned that recent fears of invasive lionfish causing fish poisoning may be unfounded. If so, current efforts to control lionfish by fishing derbies and targeted fisheries may remain the ...

Molecular gate that could keep cancer cells locked up

11 hours ago

In a study published today in Genes & Development, Dr Christian Speck from the MRC Clinical Sciences Centre's DNA Replication group, in collaboration with Brookhaven National Laboratory (BNL), New York, ...

User comments : 0