Affiliations 

  • 1 Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, 201306, China
  • 2 Molecular Population Genetics & Breeding Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Republic of Singapore
  • 3 Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China
  • 4 Molecular Population Genetics & Breeding Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Republic of Singapore. genhua@tll.org.sg
  • 5 Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, 201306, China. jlli@shou.edu.cn
BMC Genomics, 2019 Jun 07;20(1):467.
PMID: 31174480 DOI: 10.1186/s12864-019-5872-1

Abstract

BACKGROUND: Genetic diversity within a species reflects population evolution, ecology, and ability to adapt. Genome-wide population surveys of both natural and introduced populations provide insights into genetic diversity, the evolutionary processes and the genetic basis underlying local adaptation. Grass carp is the most important freshwater foodfish species for food and water weed control. However, there is as yet no overall picture on genetic variations and population structure of this species, which is important for its aquaculture.

RESULTS: We used 43,310 SNPs to infer the population structure, evidence of local adaptation and sources of introduction. The overall genetic differentiation of this species was low. The native populations were differentiated into three genetic clusters, corresponding to the Yangtze, Pearl and Heilongjiang River Systems, respectively. The populations in Malaysia, India and Nepal were introduced from both the Yangtze and Pearl River Systems. Loci and genes involved in putative local selection for native locations were identified. Evidence of both positive and balancing selection was found in the introduced locations. Genes associated with loci under putative selection were involved in many biological functions. Outlier loci were grouped into clusters as genomic islands within some specific genomic regions, which likely agrees with the divergence hitchhiking scenario of divergence-with-gene-flow.

CONCLUSIONS: This study, for the first time, sheds novel insights on the population differentiation of the grass carp, genetics of its strong ability in adaption to diverse environments and sources of some introduced grass carp populations. Our data also suggests that the natural populations of the grass carp have been affected by the aquaculture besides neutral and adaptive forces.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.