Phylogeography of willow grouse (Lagopus lagopus) in the Arctic: taxonomic discordance as inferred from molecular data JACOB HÖGLUND 1 *, BIAO WANG 1 , THOMAS AXELSSON 2 and MARÍA QUINTELA 1 † 1 Population Biology and Conservation Biology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE 75236 Uppsala, Sweden 2 Molecular Medicine, Department of Medical Sciences, University Hospital, SE 751 85 Uppsala, Sweden Received 21 November 2012; revised 10 March 2013; accepted for publication 10 March 2013 Using independently segregating nuclear single nucleotide polymorphisms (SNPs) and mitochondrial control region sequences, we found an east–west division among sampled willow grouse Lagopus lagopus subspecies. This division cut across the range of the subspecies with the largest distribution (lagopus) and thus contradicted existing taxonomic classifications. Russian Lagopus lagopus lagopus tended to cluster with North American willow grouse partly classified as other subspecies. Scandinavian willow grouse (L. l. lagopus) clustered with red grouse from Britain and Ireland (Lagopus lagopus scoticus and Lagopus lagopus hibernicus) but substructuring confirmed the monophyly of the latter. In North America, we could not detect any major genetic divisions apart from two birds described as alexandrae from the Heceta Island (Alaska) when using mitochondrial sequences. Other samples from North America were intermingled regardless of whether they were described as muriei, alexandrae or lagopus.A specimen described as alexandrae was to some extent distinct when analysing the SNP data. The genetic analyses indicated some concordance between genetics and taxonomy but not complete congruence. This is particularly evident for mitochondrial DNA network analyses. We suggest that the taxonomy of this species would benefit by a careful re-examination of the available evidence for subspecies. It appears as if subspecies status is a poor proxy for assigning evolutionary significant units and management units in this species. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 77–90. ADDITIONAL KEYWORDS: alexandrae – evolutionary significant unit – hibernicus – kamschatkensis – Lagopus lagopus – muriei – phylogeography – scoticus – willow grouse subspecies. INTRODUCTION To take accurate conservation actions, it is important to correctly identify the taxonomic units relevant for conservation (Moritz, 1994; Crandall et al., 2000; Ballard & Whitlock, 2004; Beaumont & Balding, 2004). Many conservation actions still rely on taxo- nomic subspecies classifications based on morphologi- cal characters. Although these may be valid in many instances, they should be confirmed by the genetic data because classifications based purely on morpho- logical data may be misleading as a result of pheno- typic plasticity and clinal variation (Storz, 2002; Relethford, 2004). Subsequent to the introduction of genetic techniques in conservation, it has been common practice to use mitochondrial (mt)DNA sequences to infer species and other taxonomic rela- tionships. For taxa to classify as an evolutionary significant unit (ESU), it has been suggested that they need to be reciprocally monophyletic for mtDNA alleles (Moritz, 1994). However, maternally inherited mtDNA has no (or very low) recombination rates and is thus inherited as a single linkage group (i.e. as one gene) (Ballard & Whitlock, 2004). It has long been known that single gene trees may be discordant with *Corresponding author. E-mail: jacob.hoglund@ebc.uu.se †Current address: Department of Animal Biology, Plant Biology and Ecology, Faculty of Science, University A Coruña, E-15008 A Coruña, Spain. Biological Journal of the Linnean Society, 2013, 110, 77–90. With 6 figures © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 77–90 77 Downloaded from https://academic.oup.com/biolinnean/article-abstract/110/1/77/2415694 by guest on 30 July 2018