Genetic structure among continental and island populations of gyrfalcons

Little is known about the possible influence that past glacial events have had on the phylogeography and population structure of avian predators in the Arctic and sub-Arctic. In this study, we use microsatellite and mitochondrial control region DNA variation to investigate the population genetic structure of gyrfalcons (Falco rusticolus) throughout a large portion of their circumpolar distribution. In most locations sampled, the mtDNA data revealed little geographic structure; however, five out of eight mtDNA haplotypes were unique to a particular geographic area (Greenland, Iceland, or Alaska) and the Iceland population differed from others based on haplotype frequency differences (F(ST)). With the microsatellite results, significant population structure (F(ST), principal components analysis, and cluster analysis) was observed identifying Greenland and Iceland as separate populations, while Norway, Alaska and Canada were identified as a single population consistent with contemporary gene flow across Russia. Within Greenland, differing levels of gene flow between western and eastern sampling locations was indicated with apparent asymmetric dispersal in western Greenland from north to south. This dispersal bias is in agreement with the distribution of plumage colour variants with white gyrfalcons in much higher proportion in northern Greenland. Lastly, because the mtDNA control region sequence differed by only one to four nucleotides from a common haplotype among all gyrfalcons, we infer that the observed microsatellite population genetic structure has developed since the last glacial maximum. This conclusion is further supported by our finding that a closely related species, the saker falcon (Falco cherrug), has greater genetic heterogeneity, including mtDNA haplotypes differing by 1-16 nucleotide substitutions from a common gyrfalcon haplotype. This is consistent with gyrfalcons having expanded rapidly from a single glacial-age refugium to their current circumpolar distribution. Additional sampling of gyrfalcons from Fennoscandia and Russia throughout Siberia is necessary to test putative gene flow between Norway and Alaska and Canada as suggested by this study.     

Using multiple markers to elucidate the ancient,historical and modern relationships among North American Arctic dog breeds

Throughout most of the Americas, post-colonial dogs largely erased the genetic signatures of pre-historical dogs. However, the North American Arctic harbors dogs that are potentially descended from pre-historical ancestors, as well as those affected by post-colonial translocations and admixtures. In particular, Inuit dogs from Canada and Greenland are thought to descend from dogs associated with Thule peoples, who relied on them for transportation ca. 1000 years ago. Whether Thule dogs reflected an earlier colonization by Paleoeskimo dogs ca. 4500 years ago is unknown. During the Alaskan Gold Rush, additional sled dogs, possibly of post-colonial derivation, the Alaskan Husky, Malamute and Siberian Husky, were used in the Arctic. The genealogical relationships among and origins of these breeds are unknown. Here we use autosomal, paternal and maternal DNA markers to (1) test the hypothesis that Inuit dogs have retained their indigenous ancestry, (2) characterize their relationship to one another and to other Arctic breeds, and (3) estimate the age of North American indigenous matrilines and patrilines. On the basis of the agreement of all three markers we determined that Inuit dogs have maintained their indigenous nature, and that they likely derive from Thule dogs. In addition, we provide support for previous research that the Inuit dogs from Canada and Greenland dog should not be distinguished as two breeds. The Alaskan Husky displayed evidence of European introgression, in contrast to the Malamute and Siberian Husky, which appear to have maintained most of their ancient Siberian ancestry.     

Islands in the ice: colonisation routes for rock ptarmigan to the Svalbard archipelago

The ancestors of rock ptarmigan Lagopus muta originated in the Beringia area well before the disruption of the Beringian land bridge. They spread westwards to Siberia and eastwards to the North American arctic and Greenland. The distribution of rock ptarmigan has been affected by glaciations restricting it to geographically limited refugia. Today the species has a circumpolar distribution in arctic tundra and alpine habitats, with up to 30 subspecies recognised based on morphological characters. We sequenced the mitochondrial control region for 72 individuals and genotyped 69 individuals for 12 microsatellite loci to investigate neutral genetic variation within and among five rock ptarmigan populations, Greenland, Iceland, Scandinavia, Svalbard and Taimyr. Genetic structure among the studied samples was high, overall F_ST estimated from microsatellite loci was 0.18 and only one out of 16 mtDNA haplotypes was found in more than one population. Genetic variation ( h, π, H_e, allelic richness) was slightly lower in the Svalbard population than in other populations, suggesting a low effective population size, possibly due to isolation following colonisation. An unrooted network and a phylogenetic tree showed that the Scandinavian population has diverged from the other populations by at least ten mutational steps, probably due to independent colonisation of Europe and subsequent long-term isolation, and rules out Scandinavia as a source for colonisation of Svalbard. Alignment with partial control region sequences from other studies showed that the haplotype that was central in our network and found on Svalbard and in Taimyr, most likely corresponds to a haplotype found in Siberia, Alaska and the Canadian Arctic, but not in Greenland, Scandinavia and Iceland. This suggests an eastern origin of rock ptarmigan in Svalbard, although this question cannot be settled conclusively.     

mtDNA variation among Greenland Eskimos: the edge of the Beringian expansion

The Eskimo-Aleut language phylum is distributed from coastal Siberia across Alaska and Canada to Greenland and is well distinguished from the neighboring Na Dene languages. Genetically, however, the distinction between Na Dene and Eskimo-Aleut speakers is less clear. In order to improve the genetic characterization of Eskimos in general and Greenlanders in particular, we have sequenced hypervariable segment I (HVS-I) of the mitochondrial DNA (mtDNA) control region and typed relevant RFLP sites in the mtDNA of 82 Eskimos from Greenland. A comparison of our data with published sequences demonstrates major mtDNA types shared between Na Dene and Eskimo, indicating a common Beringian history within the Holocene. We further confirm the presence of an Eskimo-specific mtDNA subgroup characterized by nucleotide position 16265G within mtDNA group A2. This subgroup is found in all Eskimo groups analyzed so far and is estimated to have originated <3,000 years ago. A founder analysis of all Eskimo and Chukchi A2 types indicates that the Siberian and Greenland ancestral mtDNA pools separated around the time when the Neo-Eskimo culture emerged. The Greenland mtDNA types are a subset of the Alaskan mtDNA variation: they lack the groups D2 and D3 found in Siberia and Alaska and are exclusively A2 but at the same time lack the A2 root type. The data are in agreement with the view that the present Greenland Eskimos essentially descend from Alaskan Neo-Eskimos. European mtDNA types are absent in our Eskimo sample.     

Mitochondrial DNA and microsatellite DNA variation in domestic reindeer (Rangifer tarandus tarandus) and relationships with wild caribou (Rangifer tarandus granti, Rangifer tarandus groenlandicus, and Rangifer tarandus caribou)

Reindeer (Rangifer tarandus tarandus) in Alaska are semidomestic livestock descended from 1280 animals introduced from Siberia, Russia, approximately 100 years ago. Genetic variation at 18 microsatellite DNA loci and the cytochrome b gene of mitochondrial DNA (mtDNA) was quantified in reindeer from Alaska, Siberia (Russia), and Scandinavia and compared with wild North American caribou. Mean sequence divergence among 15 mtDNA haplotypes in reindeer was 0.007 substitutions per nucleotide site, and reindeer mtDNA is polyphyletic with caribou mtDNA. Microsatellite allele and mtDNA haplotype frequencies are similar between Alaskan and Russian reindeer and differentiated between these and Scandinavian reindeer. The frequencies of microsatellite alleles and mtDNA haplotypes are different in reindeer and wild caribou (Rangifer tarandus granti, Rangifer tarandus groenlandicus, and Rangifer tarandus caribou). Alaskan reindeer have maintained a genetic variation comparable to that in Russia and differentiated from that of wild caribou, >100 years after their introduction to Alaska.     

Population structure and gene flow of the Atlantic walrus (Odobenus rosmarus rosmarus) in the eastern Atlantic Arctic based on mitochondrial DNA and microsatellite variation

The population structure of the Atlantic walrus, Odobenus rosmarus rosmarus , was studied using 11 polymorphic microsatellites and restriction fragment length polymorphism detected in the NADH-dehydrogenase ND1, ND2 and ND3/4 segments in mtDNA. A total of 105 walrus samples were analysed from northwest (NW) Greenland, east (E) Greenland, Svalbard and Franz Joseph Land. Two of the 10 haplotypes detected in the four samples were diagnostic for the NW Greenland sample, which implied that the group of walruses in this area is evolutionary distinct from walruses in the other three areas. One individual sampled in E Greenland exhibited a Pacific haplotype, which proved a connection between the Pacific walrus and walruses in eastern Greenland. The Franz Joseph Land, Svalbard and E Greenland samples shared the most common haplotype, indicating very little differentiation at the mtDNA level. Gene flow ( Nm ) estimates among the four areas indicated a very restricted exchange of female genes between NW Greenland and the more eastern Atlantic Arctic samples, and a closer relationship between the three samples composing the eastern Atlantic Arctic. The genetic variation at 11 polymorphic microsatellite loci grouped individuals into three populations, NW Greenland, E Greenland and a common Franz Joseph Land–Svalbard population, which were connected by moderate gene flow.     

Geographical segregation in Dunlin Calidris alpina populations wintering along the East Atlantic migratory flyway – evidence from mitochondrial DNA analysis

Dunlin Calidris alpina is one of the most abundant shorebirds using coastal habitats in the East Atlantic migratory flyway, that links arctic breeding locations (Greenland to Siberia) with wintering grounds (West Europe to West Africa). Differential migration and winter segregation between populations have been indicated by morphometrics and ringing recoveries. Here, we analyse the potential of genetic markers (mitochondrial DNA – mtDNA) to validate and enhance such findings. We compared mtDNA haplotypes frequencies at different wintering sites (from north-west Europe to West Africa). All birds from West Africa had western (European) haplotypes, while the eastern (Siberian) haplotypes were only present in European winter samples, reaching higher frequencies further north in Europe. Compilation of published results from migrating birds also confirmed these differences, with the sole presence of European haplotypes in Iberia and West Africa and increasingly higher frequencies of Siberian haplotypes from south-west to north-west Europe. Comparison with published haplotype frequencies of breeding populations shows that birds from Greenland, Iceland, and North Europe were predominant in wintering grounds in West Africa, while populations wintering in West Europe originated from more eastern breeding grounds (e.g. North Russia). These results show that genetic markers can be used to enhance the integrative monitoring of wintering and breeding populations, by providing biogeographical evidence that validate the winter segregation of breeding populations.     

The frontal sinus in ancient and modern Greenlandic Inuit

The purpose of this study was to compare the frontal sinus size of ancient Greenlandic Inuit with ancient Inuit of Alaska and Canada, and to compare sinus size between ancient and modern Greenlandic Inuit. Also, it was analyzed whether cranial size was a determinant of frontal sinus size. Frontal sinus size was evaluated in terms of absence frequency and planimetrically. Absence was defined as a frontal sinus not exceeding a line drawn between the supraorbital rims. A significant increase in absence frequency was noted from Alaska over Canada to Greenland (males: p<0.03; females p<0.0001). This is in accordance with earlier studies, indicating that although these Inuit populations once have been commonly related to the Old Bering Sea population, the Greenland Inuit represent an endpoint in an eastward migration. There was a significant increase (p<0.0001) in frontal sinus size from ancient to modern Greenlandic Inuit, probably indicative of a high degree of admixture with non-Inuit after modern colonization. The results regarding craniofacial size parameters and frontal sinus side were inconclusive. No single craniofacial variable showed significant effect on frontal sinus size, but the area displayed sexual dimorphism, females having smaller frontal sinuses.     

mtDNA diversity in Chukchi and Siberian Eskimos: implications for the genetic history of Ancient Beringia and the peopling of the New World.

The mtDNAs of 145 individuals representing the aboriginal populations of Chukotka-the Chukchi and Siberian Eskimos-were subjected to RFLP analysis and control-region sequencing. This analysis showed that the core of the genetic makeup of the Chukchi and Siberian Eskimos consisted of three (A, C, and D) of the four primary mtDNA haplotype groups (haplogroups) (A-D) observed in Native Americans, with haplogroup A being the most prevalent in both Chukotkan populations. Two unique haplotypes belonging to haplogroup G (formerly called "other" mtDNAs) were also observed in a few Chukchi, and these have apparently been acquired through gene flow from adjacent Kamchatka, where haplogroup G is prevalent in the Koryak and Itel'men. In addition, a 16111C-->T transition appears to delineate an "American" enclave of haplogroup A mtDNAs in northeastern Siberia, whereas the 16192C-->T transition demarcates a "northern Pacific Rim" cluster within this haplogroup. Furthermore, the sequence-divergence estimates for haplogroups A, C, and D of Siberian and Native American populations indicate that the earliest inhabitants of Beringia possessed a limited number of founding mtDNA haplotypes and that the first humans expanded into the New World approximately 34,000 years before present (YBP). Subsequent migration 16,000-13,000 YBP apparently brought a restricted number of haplogroup B haplotypes to the Americas. For millennia, Beringia may have been the repository of the respective founding sequences that selectively penetrated into northern North America from western Alaska.     

Population genetic structure and evolutionary history of North Atlantic beluga whales (Delphinapterus leucas) from West Greenland, Svalbard and the White Sea

Population structure in many Arctic marine mammal species reflects a dynamic interplay between physical isolating mechanisms and the extent to which dispersal opportunities are met. We examined variation within mtDNA and eight microsatellite markers to investigate population structure and demographic history in beluga whales in the North Atlantic. Genetic heterogeneity was observed between Svalbard and West Greenland that reveals limited gene flow over ecological time scales. Differentiation was also recorded between Atlantic belugas and two previously studied populations in the North Pacific, the Beaufort Sea and Gulf of Alaska. However, Bayesian cluster analysis of the nDNA data identified two population clusters that did not correspond to the respective ocean basins, as predicted, but to: (1) Arctic (Svalbard–White Sea–Greenland–Beaufort Sea) and (2) Subarctic (Gulf of Alaska) regions. Similarly, the deepest phylogeographic signal was between the Arctic populations and the Gulf of Alaska. Fitting an isolation-with-migration model yielded genetic abundance estimates that match census estimates and revealed that Svalbard and the Beaufort Sea likely diverged 7,600–35,400 years ago but have experienced recurrent periods with gene flow since then, most likely via the Russian Arctic during subsequent warm periods. Considering current projections of continued sea ice losses in the Arctic, this study identified likely routes of future contact among extant beluga populations, and other mobile marine species, which have implications for genetic introgression, health, ecology and behavior.     

Origin and history of mitochondrial DNA lineages in domestic horses

Domestic horses represent a genetic paradox: although they have the greatest number of maternal lineages (mtDNA) of all domestic species, their paternal lineages are extremely homogeneous on the Y-chromosome. In order to address their huge mtDNA variation and the origin and history of maternal lineages in domestic horses, we analyzed 1961 partial d-loop sequences from 207 ancient remains and 1754 modern horses. The sample set ranged from Alaska and North East Siberia to the Iberian Peninsula and from the Late Pleistocene to modern times. We found a panmictic Late Pleistocene horse population ranging from Alaska to the Pyrenees. Later, during the Early Holocene and the Copper Age, more or less separated sub-populations are indicated for the Eurasian steppe region and Iberia. Our data suggest multiple domestications and introgressions of females especially during the Iron Age. Although all Eurasian regions contributed to the genetic pedigree of modern breeds, most haplotypes had their roots in Eastern Europe and Siberia. We found 87 ancient haplotypes (Pleistocene to Mediaeval Times); 56 of these haplotypes were also observed in domestic horses, although thus far only 39 haplotypes have been confirmed to survive in modern breeds. Thus, at least seventeen haplotypes of early domestic horses have become extinct during the last 5,500 years. It is concluded that the large diversity of mtDNA lineages is not a product of animal breeding but, in fact, represents ancestral variability.     

On the origin of a domesticated species: Identifying the parent population of Russian silver foxes (Vulpes vulpes)

The foxes at Novosibirsk, Russia, are the only population of domesticated foxes in the world. These domesticated foxes originated from farm-bred silver foxes (Vulpes vulpes), whose genetic source is unknown. In this study we examined the origin of the domesticated strain of foxes and two other farm-bred fox populations (aggressive and unselected) maintained in Novosibirsk. To identify the phylogenetic origin of these populations we sequenced two regions of mtDNA, cytochrome b and D-loop, from 24 Novosibirsk foxes (8 foxes from each population) and compared them with corresponding sequences of native red foxes from Europe, Asia, Alaska and Western Canada, Eastern Canada, and the Western Mountains of the USA. We identified seven cytochrome b - D-loop haplotypes in Novosibirsk populations, four of which were previously observed in Eastern North America. The three remaining haplotypes differed by one or two base change from the most common haplotype in Eastern Canada. Φ(ST) analysis showed significant differentiation between Novosibirsk populations and red fox populations from all geographic regions except Eastern Canada. No haplotypes of Eurasian origin were identified in the Novosibirsk populations. These results are consistent with historical records indicating that the original breeding stock of farm-bred foxes originated from Prince Edward Island, Canada. Mitochondrial DNA data together with historical records indicate two stages in the selection of domesticated foxes: the first includes captive breeding for ~50 years with unconscious selection for behaviour; the second corresponds to over 50 further years of intensive selection for tame behaviour.     

An extensive analysis of Y-chromosomal microsatellite haplotypes in globally dispersed human populations

The genetic variance at seven Y-chromosomal microsatellite loci (or short tandem repeats [STRs]) was studied among 986 male individuals from 20 globally dispersed human populations. A total of 598 different haplotypes were observed, of which 437 (73.1%) were each found in a single male only. Population-specific haplotype-diversity values were.86-.99. Analyses of haplotype diversity and population-specific haplotypes revealed marked population-structure differences between more-isolated indigenous populations (e.g., Central African Pygmies or Greenland Inuit) and more-admixed populations (e.g., Europeans or Surinamese). Furthermore, male individuals from isolated indigenous populations shared haplotypes mainly with male individuals from their own population. By analysis of molecular variance, we found that 76.8% of the total genetic variance present among these male individuals could be attributed to genetic differences between male individuals who were members of the same population. Haplotype sharing between populations, phi(ST) statistics, and phylogenetic analysis identified close genetic affinities among European populations and among New Guinean populations. Our data illustrate that Y-chromosomal STR haplotypes are an ideal tool for the study of the genetic affinities between groups of male subjects and for detection of population structure.     

Phylogeography of mitochondrial DNA variation in brown bears and polar bears

We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.     

Haplotype Frequency Distribution in Northeastern European Saduria entomon (Crustacea: Isopoda) Populations. A Phylogeographic Approach

The distribution pattern of mtDNA haplotypes in distinct populations of the glacial relict crustacean Saduria entomon was examined to assess phylogeographic relationships among them. Populations from the Baltic, the White Sea and the Barents Sea were screened for mtDNA variation using PCR‐based RFLP analysis of a 1150 bp fragment containing part of the CO I and CO II genes. Five mtDNA haplotypes were recorded. An analysis of geographical heterogeneity in haplotype frequency distributions revealed significant differences among populations. The isolated populations of S. entomon have diverged since the retreat of the last glaciation. The geographical pattern of variation is most likely the result of stochastic (founder effect, genetic drift) mechanisms and suggests that the haplotype differentiation observed is probably older than the isolation of the Baltic and Arctic seas.     

Trans‐Pacific and trans‐Arctic pathways of the intertidal macroalga Fucus distichus L. reveal multiple glacial refugia and colonizations from the North Pacific to the North Atlantic

Aim We examined the phylogeography of the cold‐temperate macroalgal species Fucus distichus L., a key foundation species in rocky intertidal shores and the only Fucus species to occur naturally in both the North Pacific and the North Atlantic. Location North Pacific and North Atlantic oceans (42° to 77° N). Methods We genotyped individuals from 23 populations for a mitochondrial DNA (mtDNA) intergenic spacer (IGS) (n = 608) and the cytochrome c oxidase subunit I (COI) region (n = 276), as well as for six nuclear microsatellite loci (n = 592). Phylogeographic structure and connectivity were assessed using population genetic and phylogenetic network analyses. Results IGS mtDNA haplotype diversity was highest in the North Pacific, and divergence between Pacific haplotypes was much older than that of the single cluster of Atlantic haplotypes. Two ancestral Pacific IGS/COI clusters led to a widespread Atlantic cluster. High mtDNA and microsatellite diversities were observed in Prince William Sound, Alaska, 11 years after severe disturbance by the 1989 Exxon Valdez oil spill. Main conclusions At least two colonizations occurred from the older North Pacific populations to the North Atlantic between the opening of the Bering Strait and the onset of the Last Glacial Maximum. One colonization event was from the Japanese Archipelago/eastern Aleutians, and a second was from the Alaskan mainland around the Gulf of Alaska. Japanese populations probably arose from a single recolonization event from the eastern Aleutian Islands before the North Pacific–North Atlantic colonization. In the North Atlantic, the Last Glacial Maximum forced the species into at least two known glacial refugia: the Nova Scotia/Newfoundland (Canada) region and Andøya (northern Norway). The presence of two private haplotypes in the central Atlantic suggests the possibility of colonization from other refugia that are now too warm to support F. distichus. With the continuing decline in Arctic ice cover as a result of global climate change, renewed contact between North Pacific and North Atlantic populations of Fucus species is expected.     

Phenotypic and genetic differentiation of two major phylogeographical lineages of arctic grayling Thymallus arcticus in the Lena River, and surrounding Arctic drainages

Two phylogeographical lineages of arctic grayling, Thymallus arcticus , in Siberia are extensively characterized based on both molecular genetic (mtDNA control region sequences) and phenotypic (12 meristic characters) data. One lineage, occurring in the delta region of the Lena River as well as all other Arctic draining rivers sampled, corresponds to the subspecific taxon Thymallus arcticus pallasii , whose type locality is the Kolyma River. This taxon is proposed to be a postglacial colonizer of the Lena delta. The second lineage occurs throughout the rest of the Lena basin and is proposed to have survived in a glacial refugium in the middle reaches of the Lena. These lineages form reciprocally monophyletic groups based on mtDNA sequences (net divergence 3.2%), a relationship that is concordant with phenotypic data, and thus reflects distinct taxa. The upper Lena taxon is given the preliminary name of Thymallus arcticus lenensis . Phylogenetic analysis, together with previously published data from North America, reveals that mtDNA sequences from North American populations group within the diverse clade corresponding to T. a. pallasii in Siberia. Despite the relatively close genetic relationship of most North American haplotypes with those in northern Siberia, inferences of fragmentation between the continents are supported, but bidirectional movements between the two continents are seen as likely. Despite inclusion in the clade representing T. a. pallasii in Siberia, the source of the relatively divergent Nahanni refuge haplotypes in North America is not resolved. Otherwise, inferences of postglacial expansion across several thousand kilometres are well supported within North America, but only smaller-scale colonization events among drainages are supported in Siberia.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 511–525.     

Mitochondrial diversity in European and Chinese pigs is consistent with population expansions that occurred prior to domestication

Mitochondrial DNA (mtDNA) diversity in European and Asian pigs was assessed using 1536 samples representing 45 European and 21 Chinese breeds. Diagnostic nucleotide differences in the cytochrome b (Cytb) gene between the European and Asian mtDNA variants were determined by pyrosequencing as a rapid screening method. Subsequently, 637bp of the hypervariable control region was sequenced to further characterize mtDNA diversity. All sequences belonged to the D1 and D2 clusters of pig mtDNA originating from ancestral wild boar populations in Europe and Asia, respectively. The average frequency of Asian mtDNA haplotypes was 29% across European breeds, but varied from 0 to 100% within individual breeds. A neighbour-joining (NJ) tree of control region sequences showed that European and Asian haplotypes form distinct clusters consistent with the independent domestication of pigs in Asia and Europe. The Asian haplotypes found in the European pigs were identical or closely related to those found in domestic pigs from Southeast China. The star-like pattern detected by network analysis for both the European and Asian haplotypes was consistent with a previous demographic expansion. Mismatch analysis supported this notion and suggested that the expansion was initiated before domestication.     

Genetic and morphological variation in Dunlin Calidris alpina breeding in the Palearctic tundra

The extensive overlap in morphological characters between populations of Dunlin Calidris alpina imposes problems of determining the origin of migrating and wintering birds. The morphology of the birds also varies between the sexes, and the sex of a Dunlin may often be difficult to determine. To clarify if mitochondrial DNA can be used to identify which breeding areas migrating Dunlin come from, we investigated the occurrence of different mtDNA haplotypes in Dunlin from eight breeding areas on the Russian and Siberian tundra. Four haplotypes were found and at most sites more than one haplotype occurred. The European haplotype predominated in the area west of the Taymyr Peninsula, the Siberian haplotype in central Siberia (from the Taymyr Peninsula to the Lopatka Peninsula) and the Beringian haplotype in eastern Siberia. One individual of an Alaskan haplotype, not detected previously among breeding birds outside North America, was found on Wrangel Island. The sex of each bird was identified genetically and the morphology of males and females was analysed separately. Birds with the European haplotype were generally smaller than birds with the Beringian or Alaskan haplotypes. Birds possessing the Siberian haplotype showed intermediate values in most cases. After compensating for differences between sites, males with the Siberian haplotype had significantly longer bills than males having the European haplotype. Multiple regressions indicate that mitochondrial DNA analysis improves models estimating the breeding origin of migrating Dunlin.