Biodiv Sci ›› 2013, Vol. 21 ›› Issue (3): 306-314.DOI: 10.3724/SP.J.1003.2013.09029

• Orginal Article • Previous Articles     Next Articles

Population genetics and demographic history of red seaweed, Palmaria palmata, from the Canada-northwest Atlantic

Jingjing Li1,2, Jie Zhang1,2, Zimin Hu1,*(), Delin Duan1,*()   

  1. 1 Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong 266071
    2 University of Chinese Academy of Sciences, Beijing 100049
  • Received:2013-01-30 Accepted:2013-03-28 Online:2013-05-20 Published:2013-06-05
  • Contact: Hu Zimin,Duan Delin

Abstract:

The paleoclimate change (e.g. the glacial fluctuation in the late Pleistocene) played an important role in shaping species’ population genetic structure, geographic distribution patterns, and gradient of diversity and composition. In this study, we sampled eight populations (138 individuals) of Palmaria palmata, a commercially and ecologically important red macroalga found on both sides of the North Atlantic coast, aiming to assess the genetic structure and demographic history through the integration of mitochondrial cox2-3 spacer and RAPD variation. Eleven mtDNA cox2-3 haplotypes were detected, one of which (C3) was common and located centrally in a haplotype network. It is shared by all populations and is regarded as ancestral. Two northern populations from the Gulf of St. Lawrence had highest levels of genetic diversity, and were significantly divergent from all other populations. AMOVA showed that highest genetic variation for cox2-3 occurred within populations, while less existed among groups. This was consistent with the results of a STRUCTURE clustering analysis of RAPD data. Our genetic diversity and haplotype network analyses indicated that multiple glacial refugia might have existed for the species along the Canada-north- west Atlantic coast. Furthermore, Bayesian skyline plot analysis based on cox2-3 spacer sequences indicated that population size underwent a slight increase over temporal and spatial scales. This occurred in approximately 0.18-0.13 million years ago. Pairwise genetic distance (K2P) between populations from the Gulf of St. Lawrence and the Bay of Fundy was 0.2%, indicating that they diverged from their common ancestor since about 0.36 million years ago. The evidence from our study suggests that climatic oscillations during the late Pleistocene had a drastic influence on the demography and genetic diversity of P. palmatain the Canada-northwest Atlantic.

Key words: Palmaria palmata, the Last Glacial Maximum, cox2-3, genetic structure, genetic diversity