Fri Nov 16, 2012, 10:26 AM
n2doc (43,917 posts)
Tenth of Quirky Creature's Active Genes Are Foreign: Believed to 'Ingest' DNA from Other Organisms
ScienceDaily (Nov. 15, 2012) — Up to 10 per cent of the active genes of an organism that has survived 80 million years without sex are foreign, a new study from the University of Cambridge and Imperial College London reveals. The asexual organism, the bdelloid rotifer, has acquired a tenth of its active genes from bacteria and other simple organisms like fungi and algae.
The findings were reported Nov. 15 in the journal PLoS Genetics.
Bdelloid rotifers are best known for going 80 million years without sex, as they have evolved to reproduce successfully without males. Many asexual creatures go extinct without the benefit of traditional genetic evolution. However, bdelloids have flourished by developing ingenious ways of overcoming the limitations of being asexual.
Bdelloids have also developed the fascinating ability to withstand almost complete desiccation when the freshwater pools they typically live in dry up. They can survive in the dry state for many years only to revive with no ill effect once water becomes available again.
"We were thrilled when we discovered that nearly 10 per cent of bdelloids' active genes are foreign, adding to the weirdness of an already odd little creature," said Professor Alan Tunnacliffe, lead author of the study from the University of Cambridge. "We don't know how the gene transfer occurs, but it almost certainly involves ingesting DNA in organic debris, which their environments are full of. Bdelloids will eat anything smaller than their heads!"
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Tenth of Quirky Creature's Active Genes Are Foreign: Believed to 'Ingest' DNA from Other Organisms (Original post)
|The Velveteen Ocelot||Nov 2012||#1|
Response to n2doc (Original post)
Fri Nov 16, 2012, 12:50 PM
DreamGypsy (2,235 posts)
4. Rotifers in Dawkins' The Ancestors Tale
In his book The Ancestor's Tale, Richard Dawkins devote a 'Tale' in Rendezvous 26 Protostomes to Rotifers. rendezvous is a big one,occurring ~590 MYA (+/- a lot)
The beginning of the tale is:
The Rotifer's Tale
The brilliant theoretical physicist Richard Feynman is rumoured to have said, "If you think you understand quantum theory, you don't understand quantum theory.' I am tempted by an evolutionist's equivalent: 'If you think you understand sex, you don't understand sex.'
Later one we get to the bdelloid rotifers:
Bdelloidea is a large class of the phylum Rotifera. The existence of the bdelloid rotifers is an evolutionary scandal. Not my own bon mot — it rings with the unmistakable tones of John Maynard Smith. Many rotifers reproduce without sex. In this respect they resemble aphids, stick insects, various beetles and a few lizards, and are not particularly scandalous. What stuck in Maynard Smith's craw is that the bdelloids as a whole reproduce only asexually — every last one of them, evidently descended from a bdelloid common ancestor that must have lived long enough ago to beget 18 genera and 360 species. Remains in amber suggest that this male-spurning matriarch lived at least 40 million years ago, very probably more. The bdelloids are a highly successful group of animals, astonishingly numerous and a dominant part of the freshwater faunas of the world. Not a single male has ever been found.*
It's a fascinating story.
The discovery of foreign genes reported is this post adds another weird fact in the tale - evolution can proceed by acquiring genes that allow the bdelloids to survive dessication.
Great post. Thanks!