One species, two hemispheres

For the first time, researchers have demonstrated direct evidence of two polar populations of a microorganism -- one in the Arctic and the other in the Antarctic -- successfully mating and sharing the same gene pool, researchers linkurl:report this week;http://www.pnas.org/cgi/doi/10.1073/pnas.1019432108 in the Proceedings of the National Academy of Sciences.

Euplotes
Ronald Corner, linkurl:www.michigan.gov;http://www.michigan.gov/deq/0,1607,7-135-3313_3683_3720-58397--,00.html

The unique species likely overcomes its geographic divide by traveling along deep ocean currents, the authors report.linkurl:Pierangelo Luporini;http://ricerca.unicam.it/Show/Departments.aspx?Action=Data&IdUniversity=4&IdDepartment=2&IdLanguage=2 and colleagues at the University of Camerino in Italy analyzed strains of Euplotes nobilii -- a protozoan ciliate aptly named from a Greek term meaning "good swimmer" or "good sailor" -- and observed 3 strains from the Arctic and 3 from the Antarctic that successfully mated through conjugation, the direct exchange of genes, and produced viable offspring. The strains also shared structurally similar pheromones -- signaling hormones vital for cell-to-cell recognition and mating -- identified by NMR spectroscopy in collaboration with Kurt Wuthrich, winner of the linkurl:2002 Nobel Prize in Chemistry;http://nobelprize.org/nobel_prizes/chemistry/laureates/2002/wuthrich.html for the development of the technique.The ciliates most likely use cold, deep ocean currents to disperse around the globe, said Luporini. "Life is very well adapted to cold," he told The Scientist. "Cold water moves life around, and this is a good demonstration of that."In the past, researchers have proposed that plankton and other microorganisms at the two poles may be the same species, based on morphological and phenotypic observations. This is the first direct evidence that two bipolar populations cross-fertilize and share a gene pool, representing one unique species. Luporini plans to study additional populations of ciliates collected at the poles: "It may be that this is quite a general phenomenon," he added. Di Giuseppe, G. et al., "Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating," PNAS, doi:10.1073/pnas.1019432108.
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[15th December 2010] *linkurl:Arctic genes kill bacteria;http://www.the-scientist.com/blog/display/57553/
[13th July 2010] *linkurl: The Fast Track to Success;http://www.the-scientist.com/article/home/25144/
[1st November 2006]