CHARACTERISING AND UNDERSTANDING POPULATION STRUCTURE
Work is ongoing in our group and with our many collaborators to describe and explore the basis for genetic structure among populations in several species, at a range of spatial scales. For example, using techniques from landscape genetics, strong genetic structuring was recently described in Atlantic salmon in the River Moy in the West of Ireland and shown to be influenced by landscape features and population demographics (Dillane et al. 2008). We have also collaborated with others to describe sub-specific level biodiversity in salmon throughout Ireland using microsatellites (manuscript in prep.) and geographic structuring of salmon throughout the entire species range using SNPs (Bourret et al. 2013).
Previous or ongoing collaborative projects include:
Work is ongoing in our group and with our many collaborators to describe and explore the basis for genetic structure among populations in several species, at a range of spatial scales. For example, using techniques from landscape genetics, strong genetic structuring was recently described in Atlantic salmon in the River Moy in the West of Ireland and shown to be influenced by landscape features and population demographics (Dillane et al. 2008). We have also collaborated with others to describe sub-specific level biodiversity in salmon throughout Ireland using microsatellites (manuscript in prep.) and geographic structuring of salmon throughout the entire species range using SNPs (Bourret et al. 2013).
Previous or ongoing collaborative projects include:
- Biodiversity of Irish rivers and improving the National Genetic Stock Identification (NGSI) baseline
- Geographical structuring of range-wide Atlantic salmon (Salmo salar) stocks as revealed by nuclear SNPs: potential for application in the assignment to origin of marine fish
- Population genetic structure and mixed stock analysis of Lough Neagh brown trout (Salmo trutta)
- Conservation and management of brown trout in Lough Derg, Shannon River Basin, facilitated by Genetic Stock Identification (GSI)
- Using GSI to elucidate the biology and ecology of the brown trout/sea trout population complex in the Burrishoole system, west of Ireland.
- The use of novel and published microsatellite DNA marker loci for the study of population structure of cod (Gadus morhua) in the North Atlantic
- Local population structure of orange roughy (Hoplostethus atlanticus) on the Porcupine Bank
- Genetic variability and population structure of striped bass (Morone saxatilis) along the eastern seaboard of the USA
- Genetic variation of common carp (Cyprinus carpio) in Irish waters
- Population genetics in the open ocean: microsatellite DNA profiling of the pelagic blue shark (Prionace glauca)
- Genetic temporal stability in small Irish salmon river populations
- Geographical differentiation and structuring of European Atlantic salmon population groupings revealed by microsatellite loci (particularly in relation to the regional assignment of marine fish) and standardisation-calibration of genotypes in a large multi-partner research programme
- The spatial scale of genetic subdivision in populations of (Ifremeria nautilei), a hydrothermal vent gastropod from the southwest Pacific
MIXED STOCK FISHERIES ANALYSIS
Most salmon and trout-bearing rivers in the northeast Atlantic are managed on a single stock basis, without consideration of intra-river genetic structure. This despite the fact that statistically significant intra-catchment variation, usually with distinct populations homing to individual tributaries, has been known for 40 years. Various molecular methods, of increasing discriminatory power, have been utilised to demonstrate this structure, from early protein electrophoresis and allozyme studies to contemporary microsatellite DNA investigations. These studies have largely concentrated on neutral genetic variation (unaffected by natural selection) so the adaptive importance (so-called biological significance) of such structure is not clear, nor is it evident how such knowledge might be applied to within catchment management.
In order to identify biologically significant units of biodiversity, we have characterised and compared the life history traits of Atlantic salmon in individual populations or population groupings occurring within the Moy river system (Mayo, NW Ireland) by combining biological information (derived from scales) and genetic stock identification, which allows assignment of individual salmon to their within-river population. When comparing salmon from two geographically distinct areas of the Moy catchment (western and eastern tributaries separated by two large lakes, which the earlier landscape genetic study of Dillane et al. 2008 had shown to be genetically distinct), there were significant differences in size and age at maturation, in run timing of 1SW salmon, relative productivity and sea age proportions, but not in grilse smolt age between the eastern and western groupings. Such a portfolio of life histories may provide a demographic buffer, at the meta-population or stock complex scale, against environmental variability and long-term impacts such as climate change.
References:
Dillane, E., McGinnity, P., Coughlan, J. P., Cross, M. C., De Eyto, E., Kenchington, E., Prodöhl, P., & Cross, T. F. (2008). Demographics and landscape features determine intrariver population structure in Atlantic salmon (Salmo salar L.): the case of the River Moy in Ireland. Molecular Ecology, 17(22), 4786-4800.
Bourret, Vincent, Matthew P. Kent, Craig R. Primmer, Anti Vasemägi, Sten Karlsson, Kjetil Hindar, Philip McGinnity, Eric Verspoor, Louis Bernatchez, and Sigbjørn Lien. SNP‐array reveals genome‐wide patterns of geographical and potential adaptive divergence across the natural range of Atlantic salmon (Salmo salar). Molecular ecology 22, no. 3 (2013): 532-551.