Inter-Research > DAO > v91 > n1 > p35-46  
Diseases of Aquatic Organisms

via Mailchimp

DAO 91:35-46 (2010)  -  DOI:

Low genetic variation in the salmon and trout parasite Loma salmonae (Microsporidia) supports marine transmission and clarifies species boundaries

Amanda M. V. Brown1,*, Michael L. Kent2, Martin L. Adamson1

1Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
2Department of Microbiology, Oregon State University, 220 Nash Hall, Corvallis, Oregon 97331, USA

ABSTRACT: Loma salmonae is a microsporidian parasite prevalent in wild and farmed salmon species of the genus Oncorhynchus. This study compared ribosomal RNA (rDNA) and elongation factor-1 alpha (EF-1α) gene sequences to look for variation that may provide a basis for distinguishing populations. Specimens were collected from laboratory, captive (sea netpen farm and freshwater hatchery) and wild populations of fish. The host range included rainbow trout O. mykiss, Pacific salmon Oncorhynchus spp. and brook trout Salvelinus fontinalis from British Columbia, Prince Edward Island, Canada, from California, Colorado, Idaho, USA and from Chile. Both loci suggested that a variant in S. fontinalis (named ‘SV’) was a separate species. This was supported by the absence of similar variants in the source material (isolated from laboratory-held O. tshawytscha) and high divergence (1.4 to 2.3% in the rDNA and EF-1α) from L. salmonae in the type host and locality (O. mykiss in California). L. salmonae from freshwater and anadromous Oncorhynchus spp. were distinguished, providing a basis on which to evaluate possible sources of infection and suggesting geographic boundaries are important. Higher genetic variation occurred among samples of freshwater origin and from a sea netpen farm in Chile, suggesting these environments may present greater population diversity. Invariance in rDNA sequence across 17 samples from anadromous salmon in rivers, lakes, ocean, farms and hatcheries supports the hypothesis that marine transmission occurs and effectively prevents population substructuring caused by freshwater transmission.

KEY WORDS: Loma salmonae · Microsporidia · Oncorhynchus · Pacific salmon · Salmon farm · Salvelinus fontinalis · rDNA · EF-1 α

Full text in pdf format
Cite this article as: Brown AMV, Kent ML, Adamson ML (2010) Low genetic variation in the salmon and trout parasite Loma salmonae (Microsporidia) supports marine transmission and clarifies species boundaries. Dis Aquat Org 91:35-46.

Export citation
Share:    Facebook - - linkedIn

 Previous article Next article