| CaliforniaLyme 2005-10-26, 11:19 am |
| 1: Proc Biol Sci. 2005 Nov 22;272(1579):2337-44. Related Articles,
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Recurrent evolution of host-specialized races in a globally distributed
parasite.
McCoy KD, Chapuis E, Tirard C, Boulinier T, Michalakis Y, Bohec CL,
Maho YL, Gauthier-Clerc M.
Universite Paris Laboratoire de Parasitologie Evolutive VI-CNRS UMR
7103, Paris, France.
The outcome of coevolutionary interactions is predicted to vary across
landscapes depending on local conditions and levels of gene flow, with
some populations evolving more extreme specializations than others.
Using a globally distributed parasite of colonial seabirds, the tick
Ixodes uriae, we examined how host availability and geographic
isolation influences this process. In particular, we sampled ticks from
30 populations of six different seabird host species, three in the
Southern Hemisphere and three in the Northern Hemisphere. We show that
parasite races have evolved independently on hosts of both hemispheres.
Moreover, the degree of differentiation between tick races varied
spatially within each region and suggests that the divergence of tick
races is an ongoing process that has occurred multiple times across
isolated areas. As I. uriae is vector to the bacterium responsible for
Lyme disease Borrelia burgdorferi sensu lato, these results may have
important consequence for the epidemiology of this disease. With the
increased occurrence of novel interspecific interactions due to global
change, these results also stress the importance of the combined
effects of gene flow and selection for parasite diversification.
PMID: 16243689 [PubMed - in process]
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