21 Jul 2011

rotifers

A rotifer needs a man like a fish needs a bicycle
Perhaps Gloria Steinem was thinking of the microscopic creature Bdelloid rotifer when she popularized the famous feminist's catch phrase of the 70's about a woman's necessity for a man. In the rotifer's case- sisters are really doing it for themselves. You see this animal is only female and she never has sex. Never. ...for tens of millions of years. It's not that she has a headache; it's just that she doesn't need to have sex in order to have daughters. And how do we know this? This fascinating scientific tidbit was explained to me by Dr. David Mark Welch, a scientist who has been studying this organism for years.
I had an opportunity to visit Dr. Welsh in his lab located in the Josephine Bay Paul Center at the Marine Biological Laboratory. Peering through a microscope it was easy to see these transparent creatures swimming happily in a dish. The rotifer doesn't look like much. There's a mouth end, a tail end and a balloon -shaped part in between. The inner workings of this very simple creature contain all the stuff necessary to create more of the same.
But the asexual breeding is not the really cool thing about the rotifer. Although this animal lives in water it can also completely dry out and become a speck of dust. At the first drop of moisture, it rehydrates and comes back to life. This means that anywhere the wind blows, you will find one of these things hitching a ride.
Welch has done extensive work with Bdelloid rotifers and has learned that no matter what you do to these girls, nothing seems to harm them. He's blasted them with radiation, heated them to extreme temperatures and has even frozen them solid. After this punishment he added water and poof, they came back to life, no worse for the wear. His research has found that something in the DNA of the creature seems to be able to fix or mend any chromosomes damaged during the experiment.
And it turns out that rotifers have a best before date stamped on their life. They only live four weeks. But the interesting thing about those four weeks is that they are cumulative. That is to say, if you dehydrated and froze a two week old animal, kept if frozen for 6 months, then rehydrated it, the rotifer would live for only another two weeks.
Probably the most astonishing fact I learned from Dr. Welch was that NASA has to clean all probes sent into space to prevent dried rotifers from interplanetary exploration. The idea of sending something from Earth that could hatch in moisture in other places is probably not a good idea. Certainly the space agency is doing its best not to introduce alien life onto other planets. Mind you, popular music tells us, "Mars Needs Women", and the Bdelloid rotifer might just be the perfect fix.



1 comment:

Paula said...

That's a terrific and terrifying image -- the space program as a rotifer migration program!