Ice sheets and genetics: Insights into the phylogeography of Scottish Atlantic salmon, Salmo salar L.

Abstract

Main conclusions: Microsatellite differentiation in Scottish Atlantic salmon is significantly but weakly conditioned by post-LGM deglaciation, with a mosaic of regional groups and a temporal cascade of within-region CM effects caused by local range expansion as patches became deglaciated. Colonization was predominantly or exclusively from the south-western European LGM refugium. Accumulating homoplastic mutations have increasingly reduced regional differentiation.

Population genetic analysis reveals a geographically limited transition zone between two genetically distinct Atlantic salmon lineages in Norway

“…The largest genetic differences have been observed between populations inhabiting rivers on the east and west sides of the Atlantic (Gilbey, Knox, O'Sullivan, & Verspoor, 2005;Rougemont & Bernatchez, 2018;Taggart, Verspoor, Galvin, Moran, & Ferguson, 1995) and the smallest within rivers (King et al, 2005). In general, within continents, population genetic structure is further divided into smaller geographical regions (Bourret et al, 2013;Cauwelier et al, 2018;Olafsson, Pampoulie, Hjorleifsdottir, Gudjonsson, & Hreggvidsson, 2014), and thereafter, among populations inhabiting rivers within regions (Perrier, Guyomard, Bagliniere, & Evanno, 2011;Tonteri, Veselov, Zubchenko, Lumme, & Primmer, 2009;Wennevik, Skaala, Titov, Studyonov, & Naevdal, 2004). In general, within continents, population genetic structure is further divided into smaller geographical regions (Bourret et al, 2013;Cauwelier et al, 2018;Olafsson, Pampoulie, Hjorleifsdottir, Gudjonsson, & Hreggvidsson, 2014), and thereafter, among populations inhabiting rivers within regions (Perrier, Guyomard, Bagliniere, & Evanno, 2011;Tonteri, Veselov, Zubchenko, Lumme, & Primmer, 2009;Wennevik, Skaala, Titov, Studyonov, & Naevdal, 2004).…”

“…At the extreme, salmon native to the American and European continents, show differences in chromosome number (Brenna-Hansen et al, 2012;Lubieniecki et al, 2010). Detailed accounts of structuring exist for some parts of the species range (King et al, 2007), including extensive recent accounts of microsatellite variation for southern Europe (Griffiths et al, 2010;Perrier et al, 2011), Iceland (Olafsson et al, 2014), Canada (Bradbury et al, 2015), and more recently, Scotland (Cauwelier et al, 2018). Detailed accounts of structuring exist for some parts of the species range (King et al, 2007), including extensive recent accounts of microsatellite variation for southern Europe (Griffiths et al, 2010;Perrier et al, 2011), Iceland (Olafsson et al, 2014), Canada (Bradbury et al, 2015), and more recently, Scotland (Cauwelier et al, 2018).…”

“…In general, within continents, population genetic structure is further divided into smaller geographical regions (Bourret et al, 2013;Cauwelier et al, 2018;Olafsson, Pampoulie, Hjorleifsdottir, Gudjonsson, & Hreggvidsson, 2014), and thereafter, among populations inhabiting rivers within regions (Perrier, Guyomard, Bagliniere, & Evanno, 2011;Tonteri, Veselov, Zubchenko, Lumme, & Primmer, 2009;Wennevik, Skaala, Titov, Studyonov, & Naevdal, 2004). Detailed accounts of structuring exist for some parts of the species range (King et al, 2007), including extensive recent accounts of microsatellite variation for southern Europe (Griffiths et al, 2010;Perrier et al, 2011), Iceland (Olafsson et al, 2014), Canada (Bradbury et al, 2015), and more recently, Scotland (Cauwelier et al, 2018). At the finest end of the scale, genetic differences have even been observed among tributaries within larger river systems (Dillane et al, 2007(Dillane et al, , 2008Dionne, Caron, Dodson, & Bernatchez, 2009;Vaha, Erkinaro, Niemela, & Primmer, 2007).…”

“…To some extent, this will be because the level of contemporary straying among populations is a function of distance. However, other factors such as landscape features (Dillane et al, 2008), association with climate clines through local adaptation (Gilbey, Verspoor, & Summers, 1999;Jeffery et al, 2017;Verspoor, Fraser, & Youngson, 1991), and colonization history in connection with ice-cap retreat patterns (Cauwelier et al, 2018;Olafsson et al, 2014;Rougemont & Bernatchez, 2018), play an important role in shaping population genetic structure in this species. Other factors may well be involved and all are likely to be of variable importance in defining levels of within and among river population differentiation.…”

Population structure and genomic evidence for local adaptation to freshwater and marine environments in anadromous Arctic Char (Salvelinus alpinus) throughout Nunavik, Québec, Canada

“…Similar patterns were found in European lamprey species ( Lampetra spp. ), with diversity and differentiation decreasing in populations far from the Iberic glacial refugia (Mateus et al, 2018), and in Scottish populations of Atlantic Salmon, where genetic diversity was lower in more recently deglaciated regions (Cauwelier et al, 2018).…”