Bathymetric and geographic population structure in the pan-Atlantic deep-sea bivalve Deminucula atacellana (Schenck, 1939).

摘要: The deep-sea soft-sediment environment hosts a diverse and highly endemic fauna of uncertain origin. We know little about how this evolved because geographic patterns genetic variation, the essential information for inferring population differentiation speciation are poorly understood. Using formalin-fixed specimens from archival collections, we quantify variation in protobranch bivalve Deminucula atacellana, species widespread throughout Atlantic Ocean at bathyal abyssal depths. Samples were taken 18 localities North American, West European Argentine basins. A hypervariable region mitochondrial 16S rDNA was amplified by polymerase chain reaction (PCR) sequenced 130 individuals revealing 21 haplotypes. Except several important exceptions, haplotypes unique to each basin. Overall gene diversity is high ( h = 0.73) with pronounced structure (Φ ST 0.877) significant associations P < 0.0001). Sequences cluster into four major clades corresponding differences geography depth. Genetic divergence much greater among populations different depths within same basin, than those similar but separated thousands kilometres. Isolation distance probably explains interbasin variation. Depth-related may reflect historical colonization or strong environmental selective gradients. Broadly distributed organisms can possess genetically divergent populations, despite lack any morphological divergence.