etically different North and South of this barrier. Since all of these species have similar abilities to disperse, I expected to find genetic differences that corresponded to the barrier in all of them, but, surprisingly, that wasn't the case."
Mitochondrial DNA of adult fish and larvae from three locations in the Caribbean and from three locations in Brazil showed much clearer genetic differences within, rather than across, the two sides of the Amazon barrier. Genetically similar fish were found in ecologically similar habitats--even thousands of miles apart.
Wrasses collected only 360 km apart along the Brazilian coast were genetically more distinct than were fish collected 4200 km apart, from Fernando de Noronha island off of the Brazilian coast and St. Croix in the Caribbean.
The fact that evolutionary partitions correspond more closely to habitat type, rather than to conventional geographical barriers, indicates that local speciation events may overcome the homogenizing effect of migration in the ocean, vindicating Darwin's original ideas about the importance of ecological speciation in biodiversity evolution.
Page: 1 2 Related biology news :1
Contact: Beth King
Smithsonian Tropical Research Institute
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