bluuebunny/crossref_metadata_2025_split huggingface dataset:
Juxtaposed microsatellite systems as diagnostic markers for admixture: an empirical evaluation with brown trout (Salmo trutta) as model organism
Authors: Estoup A. , Largiadèr C. R. , Cornuet J.‐M. , Gharbi K. , Presa P. , Guyomard R. 
Published: March 2003

AbstractA juxtaposed microsatellite system (JMS) is composed of two microsatellite repeat arrays separated by a sequence of less than 200 bp and more than 20 bp. This paper presents the first empirical evaluation of JMSs for the study of genetic admixture induced by man, with brown trout (Salmo trutta) as model organism. Two distinct admixture situations were studied: native populations from streams of the Atlantic basin and of the Mediterranean basin, respectively, all stocked with domestic strains originating from the Atlantic basin. For these two situations, we first evaluated by simulation the ability of JMSs to differentiate between alien alleles and naturally shared homoplasious or ancestral alleles, and thus to behave as diagnostic markers for admixture. Simulations indicated that JMSs are expected to be reliable diagnostic markers in most divergent (i.e. Mediterranean) populations and nonreliable diagnostic markers in most closely related (i.e. Atlantic) populations. Three JMSs were genotyped in domestic strains as well as in nonstocked and stocked populations of brown trout sampled in different rivers of the Mediterranean and Atlantic basins. The observed distributions of JMS haplotypes were consistent with simulation predictions confirming that JMSs were reliable diagnostic markers only over a given proportion of the species range, i.e. in substantially divergent populations. JMSs also reinforced the diagnostic character of three microsatellite sites for the studied Mediterranean populations. This last result is consistent with our simulation results which showed that, although much less frequently than at JMSs, diagnostic markers are likely to be found at single site microsatellites provided that the native Mediterranean population has a sufficiently small effective population size. For each population of the Mediterranean basin admixture coefficients did not differ significantly across JMSs and mean admixture coefficients sometimes differ among populations. The interpretation of the origin of JMS haplotypes based on the allele length variants was supported by nucleotide sequence analysis.
The genetic mating system of spotted sunfish (Lepomis punctatus): mate numbers and the influence of male reproductive parasites
Authors: Dewoody J. A. , Fletcher D. E. , Mackiewicz M. , Wilkins S. D. , Avise J. C. 
Published: March 2003

AbstractIn nest‐building fish species, mature males often exhibit one of two alternative reproductive behaviours. Bourgeois males build nests, court females, and guard their eggs. Parasitic cuckolders attempt to steal fertilizations from bourgeois males and do not invest in parental care. Previous evidence from the bluegill sunfish (Lepomis macrochirus) suggests that adult males are morphologically specialized for these two tactics. Here, we used microsatellite markers to determine genetic parentage in a natural population of the spotted sunfish (L. punctatus) that also displayed both bourgeois and parasitic male morphs. As gauged by relative investments in gonadal vs. somatic tissues, between 5 and 15% of the mature adult males were parasites. Multi‐locus genotypes were generated for more than 1400 embryos in 30 nests, their nest‐guardian males, and for other adults in the population. Progeny in approximately 57% of the nests were sired exclusively by the guardian male, but the remaining nests contained embryos resulting from cuckoldry as well. Overall, the frequency of offspring resulting from stolen fertilizations was only 1.3%, indicating that the great majority of paternity is by bourgeois nesting males. With regard to maternity, 87% of the nests had at least three dams, and computer simulations estimate that about 7.2 dams spawned per nest.
Matrilinear phylogeography of Atlantic salmon (Salmo salar L.) in Europe and postglacial colonization of the Baltic Sea area
Authors: Nilsson J. , Gross R. , Asplund T. , Dove O. , Jansson H. , Kelloniemi J. , Kohlmann K. , LÖytynoja A. , Nielsen E. E. , Paaver T. , Primmer C. R. , Titov S. , VasemÄgi A. , Veselov A. , Öst T. , Lumme J. 
Published: March 2003

AbstractSixty‐four samples from 46 salmon populations totalling 2369 specimens were used for polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis of the mitochondrial ND1 region. The final analyses included 3095 specimens from 60 populations in Northern Europe. A subsample was analysed by RFLP of ND3/4/5/6. Representative RFLP haplotypes from different parts of the distribution area were sequenced and the phylogeny of European haplotypes and their relations to the North American lineage was described. The four common European haplotypes derive from the ancestral ND1‐BBBA (rooting the European clade to the North American) by one‐step substitutions: AAAA < AABA < BBBA > BBBB. The Swedish west‐coast populations differ from the geographically close southern Baltic, indicating absence of inward and limited outward gene flow through the Danish straits during the last 8000 years. Within the Baltic Sea, only three ND1 haplotypes were detected and there was no variation for ND3/4/5/6. In the whole southern Baltic and in lakes Vänern, Ladoga and Onega the haplotype AABA dominated. Proposed postglacial colonization routes to the Baltic Sea are discussed in relation to the haplotype distribution pattern.
Resistance or emigration: response of the high‐alpine plant Eritrichium nanum (L.) Gaudin to the ice age within the Central Alps
Authors: Stehlik I. , Schneller J. J. , Bachmann K. 
Published: March 2003

AbstractTwo main possibilities regarding glacial survival of the mountain flora of the Alps during the Quaternary have been discussed: the tabula rasa and the nunatak hypotheses. Eritrichium nanum (L.) Gaudin (Boraginaceae) is a perennial cushion plant, occurring at high elevations of the Central Alps and having a preference for extreme habitats. It belongs to a group of high‐alpine plants, for which in situ glacial survival on nunataks is ecologically possible. By investigating 20 populations of E. nanum of potential nunatak and peripheral refugial regions using amplified fragment length polymorphism, considerable genetic differences between populations from the Central Alps and populations from peripheral refugia were detected; hence, the latter probably did not serve as potential sources for the re‐colonization of the Central Alps after glaciation. Genetic variation was hierarchically structured (

amova), and three genetically distinct regions could be identified in the Central Alps. Two of these, the Penninic and Rhaetic Alps, correspond to nunatak regions proposed in the biogeographic literature. Populations from the Lepontic Alps formed a third genetic group. Genetic correlation (Mantel statistics) was highest within populations, with a modest decline among populations within specific nunatak regions and a negative correlation outside the genetic influence of specific nunatak regions. In situ glacial survival in E. nanum could be a model for the Quaternary history of other alpine plants, especially those that also occur at high elevations and in similar habitats.
The contribution of epistasis to species differences in annual sunflowers
Authors: Kim Seung‐Chul , Rieseberg Loren H. 
Published: March 2003

AbstractThe contribution of epistasis to 15 morphological traits differentiating two annual sunflowers (Helianthus annuus and H. debilis ssp. cucumerifolius) and to hybrid pollen sterility was estimated in a first generation backcross (BC1) mapping population. Analysis of digenic interactions among quantitative trait loci (QTLs) with significant main effects revealed significant interaction effects for six of the 15 morphological traits and for pollen sterility. Likewise, a genome‐wide scan of all possible two‐locus combinations detected additional significant interactions for three of the traits with significant epistasis in the original analysis: stem pigmentation, phyllary pubescence, and pollen viability. However, these were the only traits of the 16 examined in which detected interactions explained more than 5% of phenotypic variance. The implications of these findings for adaptive evolution and for the introgression of advantageous morphological QTLs across a natural hybrid zone between these taxa are discussed.
Differential success in northwards range expansion between ecotypes of the marble gallwasp Andricuskollari: a tale of two lifecycles
Authors: Stone Graham , Atkinson Rachel , Rokas Antonis , Csóka György , Nieves‐Aldrey José‐Luis 
Published: March 2003

AbstractThe Marble gallwasp Andricus kollari has a native range divided into two geographically separated lifecycles. In Eastern Europe and Turkey, the lifecycle involves a sexual generation on Turkey oak, Quercus cerris, while in Iberia and North Africa the sexual generation host is cork oak, Q. suber. Over the last 500 years, A. kollari has expanded its range into northern Europe, following human planting of Q. cerris from Italy and the Balkans. We ask: (i) what is the genetic relationship between eastern and western distributions of Andricus kollari? Can we determine which lifecycle is ancestral, and how long ago they diverged? (ii) To what extent have eastern and western native ranges contributed to northwards range expansion? (iii) Is there any evidence for hybridization between the two life cycle types? We present analyses of allozyme data for 13 polymorphic loci and of sequence variation for a 433 bp fragment of the mitochondrial cytochrome b gene. These show: (i) that four haplotype lineages (one in Spain, two in Hungary/Italy and one in Turkey) diverged more or less simultaneously between 1 and 2 million years ago, suggesting the existence of at least four refuges through recent ice age cycles. Our data cannot resolve which lifecycle type is ancestral. (ii) Populations north of putative refuges are divided into two sets. Populations in south‐west France are allied to Spain, while all remaining populations in northern Europe have been colonized from Italy and the Balkans. (iii) The transition from one race to another in south‐west France is marked by abrupt transitions in the frequency of refuge‐specific private alleles and corresponds closely to the northern limit of the distribution of cork oak. Although hybrids were detected in north‐west France, none were detected where the two lifecycles meet in south‐western France. The biology of oak gallwasps predicts that any hybrid zone will be narrow, and limited to regions where Q. cerris and Q. suber meet. Our data suggest that eastern and western A. kollari are effectively separate species.
Intimately linked or hardly speaking? The relationship between genotype and environmental gradients in a Louisiana Iris hybrid population
Authors: Johnston Jill A. , Wesselingh Renate A. , Bouck Amy C. , Donovan Lisa A. , Arnold Michael L. 
Published: March 2003

AbstractSeveral models of hybrid zone evolution predict the same spatial patterns of genotypic distribution whether or not structuring is due to environment‐dependent or ‐independent selection. In this study, we tested for evidence of environment‐dependent selection in anIris fulva×Iris brevicaulishybrid population by examining the distribution of genotypes in relation to environmental gradients. We selected 201 Louisiana Iris plants from within a known hybrid population (80 m × 80 m) and placed them in four different genotypic classes (I. fulva, I. fulva‐like hybrid,I. brevicaulis‐like hybrid andI. brevicaulis) based on seven species‐specific random amplified polymorphic DNA (RAPD) markers and two chloroplast DNA haplotypes. Environmental variables were then measured. These variables included percentage cover by tree canopy, elevation from the high water mark, soil pH and percentage soil organic matter. Each variable was sampled for all 201 plants. Canonical discriminant analysis (CDA) was used to infer the environmental factors most strongly associated with the different genotypic groups. Slight differences in elevation (−0.5 m to +0.4 m) were important for distinguishing habitat distributions described by CDA, even though there were no statistical differences between mean elevations alone.I. brevicaulisoccurred in a broad range of habitats, whileI. fulvahad a narrower distribution. Of all the possible combinations,I. fulva‐like hybrids andI. brevicaulis‐like hybrids occurred in the most distinct habitat types relative to one another. Each hybrid class was not significantly different from its closest parent with regard to habitat occupied, but was statistically unique from its more distant parental species. Within the hybrid genotypes, most, but not all, RAPD loci were individually correlated with environmental variables. This study suggests that, at a very fine spatial scale, environment‐dependent selection contributed to the genetic structuring of this hybrid zone.
Genetic structure of North American wolverine (Gulo gulo) populations
Authors: Kyle C. J. , Strobeck C. 
Published: March 2003

AbstractWolverines (Gulo gulo) are found in low densities throughout their circumpolar distribution. They are also potentially susceptible to human‐caused population fragmentation (development, recreation and fur harvesting). The combination of these factors has contributed to this species being listed as having either vulnerable or endangered status across much of its current range. The effects of inherently low densities and anthropogenic pressures on the genetic structure and variation of wolverine populations are, as yet, unknown. In this study, 461 individuals were typed at 12 microsatellite loci to investigate the population genetic structure of wolverines from north‐western Alaska to eastern Manitoba. Levels of gene flow and population differentiation among the sampled regions were estimated via a genotype assignment test, pairwise FST, and two genetic distance measures. Our results suggest that wolverine populations from southernmost regions, in which anthropogenic factors are strongest, revealed more genetic structuring than did northern populations. Furthermore, these results suggest that reductions in this species’ range may have led to population fragmentation in the extreme reaches of its southern distribution. The continued reduction of suitable habitat for this species may lead to more populations becoming isolated remnants of a larger distribution of northern wolverines, as documented in other North American carnivore species.
Population structure of Atlantic salmon (Salmo salar L.): a range‐wide perspective from microsatellite DNA variation
Authors: King T. L. , Kalinowski S. T. , Schill W. B. , Spidle A. P. , Lubinski B. A. 
Published: March 2003

AbstractAtlantic salmon (n = 1682) from 27 anadromous river populations and two nonanadromous strains ranging from south‐central Maine, USA to northern Spain were genotyped at 12 microsatellite DNA loci. This suite of moderate to highly polymorphic loci revealed 266 alleles (5–37/locus) range‐wide. Statistically significant allelic and genotypic heterogeneity was observed across loci between all but one pairwise comparison. Significant isolation by distance was found within and between North American and European populations, indicating reduced gene flow at all geographical scales examined. North American Atlantic salmon populations had fewer alleles, fewer unique alleles (though at a higher frequency) and a shallower phylogenetic structure than European Atlantic salmon populations. We believe these characteristics result from the differing glacial histories of the two continents, as the North American range of Atlantic salmon was glaciated more recently and more uniformly than the European range. Genotypic assignment tests based on maximum‐likelihood provided 100% correct classification to continent of origin and averaged nearly 83% correct classification to province of origin across continents. This multilocus method, which may be enhanced with additional polymorphic loci, provides fishery managers the highest degree of correct assignment to management unit of any technique currently available.
A comparison of nuclear and mitochondrial cline shapes in a hybrid zone in theSceloporus grammicuscomplex (Squamata; Phrynosomatidae)
Authors: Marshall Jonathon C. , Sites Jack W. 
Published: March 2003

AbstractThe F5 and FM2 chromosome races of theSceloporus grammicuscomplex form a hybrid zone in the Mexican state of Hidalgo. Previous studies of this zone have assessed genetic structure by averaging estimates of shape and width across three diagnostic chromosome markers. This approach is likely to mask subtle differences in cline shape among loci (e.g. selected vs. neutral), and obscure any displacement of cline centres (if present). Here we use maximum likelihood methods to construct the best fitting individual clines for three chromosomal markers, and also add two new markers; the mitochondrial DNA (mtDNA) locus, and the nuclear ribosomal DNA (rDNA) repeat. For each locus, hybrid zone models were fitted by cline shape and width, and the position and number of segments describing the centre of the zone. Pairwise comparisons between all clines revealed concordance between chromosomes 2 and 6, but significant discordance in cline structure among all other paired combinations. The concordance of chromosomes 2 and 6 suggests that these clines are maintained by genome‐wide forces. The discordance of the chromosome 1 cline suggests an influence of asymmetric introgression, while the mtDNA cline is probably influenced by selection and drift. The rDNA locus reveals a pattern best explained by either extreme asymmetric introgression or gene conversion. The structure of zone indicates that genome‐wide processes and locus specific selective forces as well as drift, are operating to different degrees on different loci. The locus‐by‐locus approach used here permits a finer discrimination among possible mechanisms responsible for the maintenance of the individual clines.
Allozymic evidence of parapatric differentiation of brown trout (Salmo trutta L.) within an Atlantic river basin of the Iberian Peninsula
Authors: Bouza C. , Castro J. , Sánchez L. , Martínez P. 
Published: March 2003

AbstractThe genetic variation of brown trout from Duero, one of the main Atlantic Iberian river basins, was assessed at 34 enzymatic loci in 62 native populations. A strong intrabasin differentiation was detected (GST = 0.46; range D: 0–0.066), mainly attributable to the existence of two divergent groups of populations within Duero: southern and northern groups. This divergence was mainly a consequence of the unequal distribution of *75 and *100 alleles at sMDH‐B1,2* isoloci, which were correlated with substantial differences in genetic diversity among regions. The Lower Course region (nearly fixed for the *100 allele) and Pisuerga River (nearly fixed for the *75 allele) showed lower heterozygosities (H ≈ 0.8%) in contrast with adjacent areas, which evidenced intermediate frequencies for both alleles and higher heterozygosities (H: 2.2–3.1%). Vicariance appeared as the more probable explanation for the significant positive correlation detected between genetic and geographical distances in Duero Basin. Genetic relationships with adjacent Iberian drainages indicate a close similarity between the southern group and Cantabric trout, whereas the northern group constitutes an ancient form from this basin. This study confirmed complex genetic relationships in brown trout from northwest Iberia, reasserting the existence of clines at several loci and for genetic diversity. The interaction between Cantabric and Duero trout, as well as the location of the limit of the anadromous form around the 42° N parallel, are both required to understand the genetic characteristics of brown trout from this area.
Phylogeography of Cape Verde Island skinks (Mabuya)
Authors: Brown R. P. , Suarez N. M. , Smith A. , Pestano J. 
Published: March 2003

AbstractThe Cape Verde Islands are of volcanic origin with most having appeared between the early Miocene and mid‐Pleistocene. They contain six known species of Mabuya skinks. Phylogeographical relationships within and among the relatively widespread taxa M. stangeri, M. spinalis and M. delalandii were inferred, based on ≈ 1 kbp of the cytochrome b gene (mitochondrial DNA). Reciprocal monophyly of M. spinalis and M. stangeri was established, which may have arisen from an early Pliocene/late Miocene cladogenetic event. Considerable between‐island sequence divergence was detected among M. spinalis, which appears to have colonized the older islands (Sal and Boavista) first. Much lower sequence divergence was found in M. delalandii, indicating a more recent range expansion. Here, evidence points to colonization of the younger islands of Brava and Fogo soon after appearance. There are similarities between some of the described patterns and those seen in lizards from the Canary Islands.
Gene flow, dispersal, and nested clade analysis among populations of the stonefly Peltoperla tarteri in the southern Appalachians
Authors: Schultheis A. S. , Weigt L. A. , Hendricks A. C. 
Published: March 2003

AbstractWe examined the genetic structure and phylogeography of populations of the stonefly Peltoperla tarteri in the Southern Appalachians to determine the extent and likely mechanism for dispersal of this stream insect. A 454‐base‐pair (bp) portion of the mitochondrial control region was sequenced from a minimum of 20 individuals from eight populations. Pairwise FST and exact tests showed high levels of differentiation among almost all populations except those on the same stream. amova analysis detected significant genetic differentiation between streams within drainages (φSD = 0.14, P < 0.001), and there was a slight positive correlation between aquatic distance and genetic distance (r = 0.295, P = 0.03). According to nested clade analysis, the present day pattern of genetic variation in P. tarteri is the result of a historical range expansion coupled with restricted gene flow with isolation by distance. Together, these analyses suggest that adult dispersal is limited and that movement by larvae is the primary dispersal mechanism for P. tarteri.