Low mitochondrial diversity and small effective population sizes of the copepods Calanus finmarchicus and Nannocalanus minor: possible impact of climatic variation during recent glaciation

Molecular diversity and population sizes of the mitochondrial 16S rRNA gene were investigated in two species of the North Atlantic planktonic copepods, Nannocalanus minor and Calanus finmarchicus. The objective of the study was to determine whether the two species, which differ in patterns of distribution, abundance and life history, would have different patterns of population genetic diversity and structure in response to climatic changes during the last glacial period. Results showed that both copepods have small effective population sizes and low mitochondrial diversity.