Sex-biased gene flow in Spectacled Eiders (Anatidae): inferences from molecular markers with contrasting modes of inheritance

ArticleinEvolution 55(10):2105-15 · November 2001with14 Reads
DOI: 10.1554/0014-3820(2001)055[2105:SBGFIS]2.0.CO;2 · Source: PubMed
Abstract
Genetic markers that differ in mode of inheritance and rate of evolution (a sex-linked Z-specific microsatellite locus, five biparentally inherited microsatellite loci, and maternally inherited mitochondrial [mtDNA] sequences) were used to evaluate the degree of spatial genetic structuring at macro- and microgeographic scales, among breeding regions and local nesting populations within each region, respectively, for a migratory sea duck species, the spectacled eider (Somateria fisheri). Disjunct and declining breeding populations coupled with sex-specific differences in seasonal migratory patterns and life history provide a series of hypotheses regarding rates and directionality of gene flow among breeding populations from the Indigirka River Delta, Russia, and the North Slope and Yukon-Kuskokwim Delta, Alaska. The degree of differentiation in mtDNA haplotype frequency among breeding regions and populations within regions was high (phiCT = 0.189, P < 0.01; phiSC = 0.059, P < 0.01, respectively). Eleven of 17 mtDNA haplotypes were restricted to a single breeding region. Genetic differences among regions were considerably lower for nuclear DNA loci (sex-linked: phiST = 0.001, P > 0.05; biparentally inherited microsatellites: mean theta = 0.001, P > 0.05) than was observed for mtDNA. Using models explicitly designed for uniparental and biparentally inherited genes, estimates of spatial divergence based on nuclear and mtDNA data together with elements of the species' breeding ecology were used to estimate effective population size and degree of male and female gene flow. Differences in the magnitude and spatial patterns of gene correlations for maternally inherited and nuclear genes revealed that females exhibit greater natal philopatry than do males. Estimates of generational female and male rates of gene flow among breeding regions differed markedly (3.67 x 10(-4) and 1.28 x 10(-2), respectively). Effective population size for mtDNA was estimated to be at least three times lower than that for biparental genes (30,671 and 101,528, respectively). Large disparities in population sizes among breeding areas greatly reduces the proportion of total genetic variance captured by dispersal, which may accelerate rates of inbreeding (i.e., promote higher coancestries) within populations due to nonrandom pairing of males with females from the same breeding population.
    • "The species was listed as threatened under the U.S. Endangered Species Act in 1993 (U.S. Fish and Wildlife Service 1993) as a result of a dramatic decline (as much as 96% from 1952 to 1993) in the western Alaska breeding population. Geographically separated and genetically distinct breeding populations also occur in northern Alaska, USA, and northern Russia (Scribner et al. 2001). Petersen et al. (1995Petersen et al. ( , 1999) used satellite telemetry to locate the species' 4 principal marine molting areas and sole wintering area in the northern Bering Sea; however, technological limitations at the time precluded data collection beyond early winter. "
    [Show abstract] [Hide abstract] ABSTRACT: Shifts in the distribution of benthivorous predators provide an indication of underlying environmental changes in benthic-mediated ecosystems. Spectacled Eiders (Somateria fischeri) are benthivorous sea ducks that spend the nonbreeding portion of their annual cycle in the Bering, Chukchi, Beaufort, and East Siberian seas. Sea ducks generally molt in biologically productive areas with abundant prey. If the distribution of eiders at molting areas matches prey abundance, spatial shifts may indicate changes in environmental conditions in the Arctic. We used a randomization procedure to test for shifts in the distribution of satellite telemetry locations received from Spectacled Eiders in the 1990s and 2008-2011 within 4 late-summer, ice-free molting areas: Indigirka-Kolyma, northern Russia; Ledyard Bay, eastern Chukchi Sea; Norton Sound, northeastern Bering Sea; and Mechigmenskiy Gulf, northwestern Bering Sea. We also tested for interannual and interdecadal changes in dive depth required to reach prey, which might affect the energetic costs of foraging during the molting period. Transmitter-marked birds used each molting area in each year, although the distribution of Spectacled Eiders shifted within each area. Interdecadal shifts in Ledyard Bay and Norton Sound decreased dive depth in recent years, although minor differences in depth were biologically negligible in relation to the energetic expense of feather growth. Shifts in Mechigmenskiy Gulf and Indigirka-Kolyma did not occur consistently within or among decades, which suggests greater interannual variability among environmental factors that influence distribution in these areas. Shifts in each molting area suggest dynamic ecosystem processes, with implications for Spectacled Eiders if changes result in novel competition or predation, or in shifting prey regimes.
    Full-text · Article · Aug 2016
    • "Genetic markers have been employed to characterise patterns of genetic variation within and among populations, and to examine the processes of dispersal and the patterns of mating that influence levels of genetic differentiation in ecosystems (Nevo et al., 1984, Parker et al., 1998 ). To achieve these aims in waterfowl species various techniques have been used: protein polymorphism (Kuznetsov et al., 1995Kuznetsov et al., , 1998 Rhodes et al., 1996; Sruoga et al., 1998; ), microsatellite polymorphism (McCracken et al., 2001; Williams et al., 2002; Slavenaite et al., 2004; Sruoga et al., 2005; Ahmadi et al., 2007), RAPD (Kulikova et al., 2003), mtDNA haplotypes (Scribner et al., 2001; Pearce et al., 2004; Kulikova et al., 2005), genetic maps (Huand et al., 2006), and MHC genes (Xia et al., 2004 ). These studies have contributed an evolutionary dimension to our understanding of contemporary ecological processes and the role of various organisms in ecosystems. "
    Full-text · Dataset · Apr 2015 · Ibis
    • "This supports the possibility that winter pairing contributes to the avoidance of inbreeding. The level of genetic variation within Northern Pintail and other dabbling duck populations might result from gene flow that is determined in the wintering grounds (Robertson & Cooke 1999, Scribner et al. 2001, Liu et al. 2013). We show that, at least in the case of Nothern Pintail, overwintering male and female juveniles in the south of Europe have different geographical origins. "
    [Show abstract] [Hide abstract] ABSTRACT: Natural and anthropogenic Iberian wetlands in Southern Europe are well known for supporting large numbers of migratory Palearctic waterbirds each winter. However, information on the geographical origin of dabbling ducks overwintering in these wetlands is scarce and mostly limited to data from ringing recoveries. Here, we used intrinsic isotopic markers to determine the geographical origin of male and female Northern Pintails Anas acuta and Eurasian Teal Anas crecca in Extremadura, inland Iberia, a key site for overwintering dabbling ducks. Additionally, we fitted six Northern Pintails with GPS-GSM tags to complement the data derived from stable isotope analysis. Most (> 70 %) first calendar-year Northern Pintails were assigned to regions above 55º N, flying 2600–5600 km from their main natal regions to Extremadura. Mean values of δ2Hf varied significantly between male and female Northern Pintails, suggesting that the sexes had different geographical origins. Data from tagged adult Northern Pintails supported the isotopic data, one male flying more than 5000 km to the coast of the Pechora Sea (Russia). Most (> 70 %) first calendar-year Eurasian Teal were assigned to the region between 48º and 60º N, travelling 1500–4500 km to arrive in Extremadura. Male and female Eurasian Teal showed marginal differences in mean values of δ2Hf. In migratory dabbling ducks, pairing typically occurs on the wintering grounds, and ducks in their first winter can breed the following spring. For Northern Pintails, pair formation in Extremadura could occur between individuals with different geographical origins, which could contribute to the genetic variability of their offspring.This article is protected by copyright. All rights reserved.
    Full-text · Article · Feb 2015
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