bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitochondrial DNA variation in rainbow trout (Oncorhynchus mykiss) across its native range: testing biogeographical hypotheses and their relevance to conservation
Authors: McCusker Megan R. , Parkinson Eric , Taylor Eric B. 
Published: March 2003

AbstractNorth‐western North America has been repeatedly glaciated over most of the past two million years, with the most recent glaciation occurring between 60 000 and 10 000 years ago. Intraspecific genetic variation in many species has been shaped by where they survived glaciation and what postglacial recolonization routes were used. In this study, molecular techniques were used to investigate biogeographical, taxonomic and conservation issues in rainbow trout, Oncorhynchus mykiss. Mitochondrial DNA (mtDNA) variation was assessed using a restriction fragment length polymorphism (RFLP) analysis, focusing mainly on the previously understudied northern extent of the species’ range. Two phylogenetically distinct mitochondrial lineages were found that differed from each other by up to 1.8% in sequence. Although the geographical distributions of the two clades overlap extensively, diversity and distributional analyses strongly suggest that trout survived glaciation in both coastal and inland refugia followed by postglacial gene flow and secondary contact. Postglacial dispersal into British Columbia most likely occurred from the Queen Charlotte Islands and the Columbia River. Although trout most likely also survived glaciation along the coast of Washington, Oregon and California, as well as near the Bering Strait, evidence suggests that dispersal into British Columbia from these areas was limited. Sequence analysis of mitochondrial haplotypes revealed higher diversity in California than in the northern part of the species’ range, indicating an ancient presence of the species in the south. Phylogeographic divergence probably predates adaptive variation in the species as suggested by evidence for parallel evolution of life history types across the range of O. mykiss.
Partial nucleotide sequences, and routine typing by polymerase chain reaction–restriction fragment length polymorphism, of the brown trout (Salmo trutta) lactate dehydrogenase, LDH‐C1*90 and *100 alleles
Authors: McMeel O. M. , Hoey E. M. , Ferguson A. 
Published: March 2003

AbstractThe cDNA nucleotide sequences of the lactate dehydrogenase alleles LDH‐C1*90 and *100 of brown trout (Salmo trutta) were found to differ at position 308 where an A is present in the *100 allele but a G is present in the *90 allele. This base substitution results in an amino acid change from aspartic acid at position 82 in the LDH‐C1 100 allozyme to a glycine in the 90 allozyme. Since aspartic acid has a net negative charge whilst glycine is uncharged, this is consistent with the electrophoretic observation that the LDH‐C1 100 allozyme has a more anodal mobility relative to the LDH‐C1 90 allozyme. Based on alignment of the cDNA sequence with the mouse genomic sequence, a local primer set was designed, incorporating the variable position, and was found to give very good amplification with brown trout genomic DNA. Sequencing of this fragment confirmed the difference in both homozygous and heterozygous individuals. Digestion of the polymerase chain reaction products with BslI, a restriction enzyme specific for the site difference, gave one, two and three fragments for the two homozygotes and the heterozygote, respectively, following electrophoretic separation. This provides a DNA‐based means of routine screening of the highly informative LDH‐C1* polymorphism in brown trout population genetic studies. Primer sets presented could be used to sequence cDNA of other LDH* genes of brown trout and other species.
Use of amplified fragment length polymorphism markers to assess genetic diversity of Lolium species from Portugal
Authors: Cresswell A. , Sackville Hamilton N. R. , Roy A. K. , Viegas B. M. F. 
Published: March 2003

AbstractWe evaluated the use of amplified fragment length polymorphism (AFLP) markers to distinguish genotypes, populations and species of Lolium. Accessions of two species Lolium perenne and Lolium multiflorum and their hybrid Lolium × hybridum, collected by the Institute of Grass and Environmental Research in 1995 from locations across Portugal, were used. The genetic variation within and between populations from the extremes of latitude and altitude was determined and assessed. Three primer pair combinations generated 765 polymorphic bands. Principal coordinate analysis of similarities between 127 plants showed high dimensionality in the data. Axes 1–3 were associated primarily with species differences, axes 4–14 with population differences within species and axis 15 onwards with within population differences. UPGMA analysis confirmed the groupings. The three populations of L. perenne formed a discrete cluster widely separated from all other populations. There were two distinct groups of L. × hybridum, of which one was similar to and overlapped with L.multiflorum and the second formed a distinct cluster. Analyses of individual bands showed that every inter‐ and intraspecific contrast involved a different sets of bands, again confirming the high dimensionality of the data. No single band was strictly diagnostic of any population or species. Nevertheless, the UPGMA analysis showed little or no overlap between populations. Thus, despite the high ratio of within‐to‐between population genetic variance, the full AFLP banding pattern of each genotype is a relatively reliable fingerprint diagnostic of its parent population. The high dimensionality implies that many different factors contribute to the differences observed. This adds to the potential value of the methodology, since it implies that there is a reasonably high likelihood of finding bands relevant to a given environmental gradient or other factor influencing the distribution of genetic diversity.
Low reproductive success in territorial male Antarctic fur seals (Arctocephalus gazella) suggests the existence of alternative mating strategies
Authors: Gemmell Neil J. , Burg Theresa M. , Boyd Ian L. , Amos William 
Published: March 2003

AbstractMicrosatellites were used to conduct an analysis of paternity of Antarctic fur seals (Arctocephalus gazella) from Bird Island, South Georgia. At most, only 28% of pups at our study site could be assigned a father, even though the majority (~90%) of candidate males within this colony were sampled. The behavioural and genetic evidence from this study suggests that a number of alternative mating strategies may exist within this fur seal population. Holding a land‐based territory conferred an advantage to male reproductive success. However, this advantage was much smaller than expected from behavioural observations. At least 70% of fur seal pups born at our study site in a given year are not fathered by males who held a territory or were observed copulating with females in the previous year, implying that there exists a pool of males that seldom venture ashore at this site. To explain this discrepancy we suggest that female choice is an integral component of the Antarctic fur seal mating system and that aquatic mating may play a much larger role in the Antarctic fur seal than previously thought.
Raciation and speciation in house mice from the Alps: the role of chromosomes
Authors: Piálek Jaroslav , Hauffe Heidi C. , Rodríguez‐Clark Kathryn M. , Searle Jeremy B. 
Published: March 2003

AbstractThere are at least 24 different karyotypic races of house mouse in the central Alps, each characterized by a different complement of ancestral acrocentric and derived metacentric chromosomes; altogether 55 different metacentric chromosomes have been described from the region. We argue that this chromosome variation largely arosein situ. If these races were to make contact, in most cases they would produce F1hybrids with substantial infertility (sometimes complete sterility), due to nondisjunction and germ cell death associated with the formation of long‐chain and/or ring configurations at meiosis. We present fertility estimates to confirm this for two particular hybrid types, one of which demonstrates male‐limited sterility (in accordance with Haldane’s Rule). As well as a model for speciation in allopatry, the Alpine mouse populations are of interest with regards speciation in parapatry: we discuss a possible reinforcement event. Raciation of house mice appears to have happened on numerous occasions within the central Alps. To investigate one possible source of new karyotypic races, we use a two‐dimensional stepping stone model to examine the generation of recombinant races within chromosomal hybrid zones. Using field‐derived ecological data and laboratory‐derived fertility estimates, we show that hybrid karyotypic races can be generated at a reasonable frequency in simulations. Our model complements others developed for flowering plants that also emphasize the potential of chromosomal hybrid zones in generating new stable karyotypic forms.
Spawning success in Atlantic salmon (Salmo salar L.): a long‐term DNA profiling‐based study conducted in a natural stream
Authors: Taggart J. B. , McLaren I. S. , Hay D. W. , Webb J. H. , Youngson A. F. 
Published: March 2003

AbstractSpawning success of Atlantic salmon (Salmo salar L.) was investigated, under near‐natural conditions, in the Girnock Burn, an 8‐km long tributary of the River Dee in Scotland. Employing minisatellite‐based DNA profiling, mating outcomes were resolved over three spawning seasons by assigning parentage to progeny samples removed from spawning nests (‘redds’). While individual spawning patterns differed markedly, consistent trends were present over the 3 years studied. Multiple spawning was found to be prevalent. More than 50% of anadromous spawners of both sexes contributed to more than one redd. Up to six redds for a single female and seven for a single male were detected. Both sexes ranged extensively. Distance between redds involving the same parent varied from a few metres to > 5 km. Distances > 1 km were common. Both males and females ranged to a similar extent. Range limit was not correlated to fish size. Pairs were not monogamous, both males and females mating with different partners at different sites. Size assortative mating was apparent among 1991 spawners but was not detected for 1992 or 1995. Redd superimposition was found to be common (17–22% of redds over the 3 years), although it was not correlated to the number of anadromous spawners present. High levels of nonanadromous mature parr mating success (40–50% of total progeny sampled) were recorded, and these likely contribute greatly to the effective population size. The relevance of these findings at the individual and population level is discussed, with particular reference to management implications.
Breeding origin and migration pattern of dunlin (Calidris alpina) revealed by mitochondrial DNA analysis
Authors: Wennerberg L. 
Published: March 2003

AbstractThe large‐scale migration of birds has been studied extensively by recoveries of ringed birds. However, there is very little ringing data from the arctic breeding grounds of waders. Here, the migration pattern of the dunlin, Calidris alpina, is studied with population genetic markers, using haplotype frequencies to estimate the breeding origin of migrating and wintering populations. Polymerase chain reaction (PCR) and restriction analysis of DNA from the mitochondrial control region was used to study the breeding origins of morphologically similar winter populations in the western Palaearctic, and to describe the population structure of the dunlin during winter. Also migrating dunlin from various stopover sites in Europe, Africa and Asia, were analysed with respect to their mitochondrial DNA (mtDNA) haplotypes. The genetic markers clearly show that the dunlin has a parallel migration system, with populations breeding in the western Palaearctic wintering mainly in the western part of the wintering range, and dunlin populations breeding further east wintering further east. The results also show that the distance between breeding and wintering area increases eastwards in this region.
Assignment of paternity groups without access to parental genotypes: multiple mating and developmental plasticity in squid
Authors: Emery A. M. , Wilson I. J. , Craig S. , Boyle P. R. , Noble L. R. 
Published: March 2003

AbstractWe present a novel approach to investigating sibling relationships and reconstructing parental genotypes from a progeny array. The Bayesian method we have employed is flexible and may be applicable to a variety of situations in addition to the one presented here. While mutation rates and breeding population allele frequencies can be taken into account, the model requires relatively few loci and makes few assumptions. Paternity of 270 veined squid (Loligo forbesi) hatchlings from three egg strings collected from one location was assigned using five microsatellite loci. Paternal and maternal genotypes reconstructed for each of the three strings were identical, strongly indicating that a single female produced the strings that were fertilized by the same four males. The proportion of eggs fertilized was not equal between males in all three strings, with male 1 siring most offspring (up to 68% in string 1), through to male 4 siring the least (as low as 2.4% in string 1). Although temperature had a profound effect on incubation time, paternity did not affect this trait at 12 °C or 8 °C.
Demic structure and its relation with the distribution of an adaptive trait in Danish flea beetles
Authors: De Jong P. W. , De Vos H. , Nielsen J. K. 
Published: March 2003

AbstractThe flea beetlePhyllotreta nemorumis an oligophagous species using crucifers as host plants. In Denmark two populations have been found which useBarbarea vulgarisssp.arcuata(G‐type) as a host plant, whereas this plant is unsuitable for the survival of the majority ofP. nemorum. In the locations in which these two populations occur, alternative host plants are also present. The plants occur in patches, some of which contain a mixture of host plants. In this study of allozyme variation, genetic differentiation betweenP. nemorumusing different host plants in patches in the two different localities was studied hierarchically to assess substructuring of the populations. Evidence was found for low, but significant, amounts of genetic differentiation between (sub)populations using spatially separated plant patches at a distance of ≈100 m to 1 km (θ = 0.009) and between localities ≈ 44 km apart (θ = 0.026), and there was an association between genetic differentiation and geographical distance. No genetic differentiation was found between beetles from different host plants with overlapping local distributions. No evidence was thus found for sympatric host race formation. The geographical distribution of genes enablingP. nemorumto useB. vulgarisas a host plant (100%‘resistant’ beetles in samples fromB. vulgaris, but much fewer on patches containing only alternative host plants) contrasts with the relatively low amount of genetic differentiation at the neutral allozyme loci. This distribution of ‘resistant’ beetles (toB. vulgarisdefence) is likely to be influenced by local differences in selection and asymmetric gene flow.
Microsatellite diversity associated with ecological factors in Hordeum spontaneum populations in Israel
Authors: Turpeinen Timo , Tenhola Teija , Manninen Outi , Nevo Eviatar , Nissilä Eero 
Published: March 2003

AbstractMicrosatellite diversity at 18 loci was analysed in 94 individual plants of 10 wild barley, Hordeum spontaneum (C. Koch) Thell., populations sampled from Israel across a southward transect of increasing aridity. Allelic distribution in populations was not distributed randomly. Estimates of mean gene diversity were highest in stressful arid‐hot environments. Sixty‐four per cent of the genetic variation was partitioned within populations and 36% between populations. Associations between ecogeographical variables and gene diversity, He, were established in nine microsatellite loci. By employing principle component analysis we reduced the number of ecogeographical variables to three principal components including water factors, temperature and geography. At three loci, stepwise multiple regression analysis explained significantly the gene diversity by a single principal component (water factors). Based on these observations it is suggested that simple sequence repeats are not necessarily biologically neutral.
Y chromosome haplotyping in Scandinavian wolves (Canis lupus) based on microsatellite markers
Authors: Sundqvist A.‐K. , Ellegren H. , Olivier M. , Vilà C. 
Published: March 2003

AbstractThe analysis of mitochondrial DNA sequences has for a long time been the most extensively used genetic tool for phylogenetic, phylogeographic and population genetic studies. Since this approach only considers female lineages, it tends to give a biased picture of the population history. The use of protein polymorphisms and microsatellites has helped to obtain a more unbiased view, but complementing population genetic studies with Y chromosome markers could clarify the role of each sex in natural processes. In this study we analysed genetic variability at four microsatellite loci on the canid Y chromosome. With these four microsatellites we constructed haplotypes and used them to study the genetic status of the Scandinavian wolf population, a population that now contains 60–70 animals but was thought to have been extinct in the 1970s. In a sample of 100 male wolves from northern Europe we found 17 different Y chromosome haplotypes. Only two of these were found in the current Scandinavian population. This indicates that there should have been at least two males involved in the founding of the Scandinavian wolf population after the bottleneck in the 1970s. The two Scandinavian Y chromosome haplotypes were not found elsewhere in northern Europe, which indicates low male gene flow between Scandinavia and the neighbouring countries.
Introgressive hybridization inRorippa(Brassicaceae): gene flow and its consequences in natural and anthropogenic habitats
Authors: Bleeker W. , Hurka H. 
Published: March 2003

AbstractIntrogressive hybridization between threeRorippaspecies (R. amphibia,R. palustrisandR. sylvestris) in northern Germany has been studied using isozymes and noncoding chloroplast DNA (trnL/F spacer). Our results provide substantial evidence for different patterns of gene flow in natural and in anthropogenic environments. Hybridization and bi‐directional introgression (chloroplast DNA and allozymes) betweenR. amphibiaandR. sylvestriswere detected at the river Elbe, which is one of the last rivers in Central Europe showing a natural dynamic of erosion and sedimentation. The natural dynamic of the Elbe leads to periodic habitat disturbance and the temporal breakdown of ecological isolation barriers betweenR. amphibiaandR. sylvestris. However, the high dynamic does not provide the opportunity for persistence of the morphologically intermediate hybridR. × anceps(R. amphibia × R. sylvestris). We did not find hybrid zones betweenR. amphibiaandR. sylvestrisin the more anthropogenic landscape of northwest Germany. However, contact zones betweenR. amphibiaandR. palustriswere detected in drainage ditches in northwest Germany. We found substantial evidence for unidirectional introgression ofR. palustrismarkers (chloroplast DNA and allozymes) intoR. amphibiain the man‐made habitats. TheR. amphibiaintrogressants in the drainage ditches often showed strongly serrate upper cauline leaves instead of the entire upper cauline leaves typical forR. amphibia. We argue that landscape melioration in northwest Germany, particularly the creation of drainage ditches, favoured both hybrid‐zone formation and ecotypic differentiation withinR. amphibia.
Fine‐scale genetic structure, estuarine colonization and incipient speciation in the marine silverside fishOdontesthes argentinensis
Authors: Beheregaray Luciano B. , Sunnucks Paul 
Published: March 2003

AbstractThe idengification of incipient ecological species represents an opportunity to investigate current evolutionary process where adaptive divergence and reproductive isolation are associated. In this study we analysed the genetic structure of marine and estuarine populations of the silverside fishOdontesthes argentinensisusing nine microsatellite loci and 396 bp of the mitochondrial DNA (mtDNA) control region. Our main objective was to investigate the relationship among estuarine colonization, divergent selection and speciation in silversides. Significant genetic structure was detected among all marine and estuarine populations. Despite the low phylogeographic structure in mtDNA haplotypes, there was clear signal of local radiations of haplotypes in more ancient populations. Divergence among marine populations was interpreted as a combined result of homing behaviour, isolation by distance and drift. On the other hand, ecological shifts due to the colonization of estuarine habitats seem to have promoted rapid adaptive divergence and reproductive isolation in estuarine populations, which were considered as incipient ecological species. This conclusion is supported by the existence of a set of environmental factors required for successful reproduction of estuarine ecotypes. The pattern of genetic structure indicates that phenotypic and reproductive divergence evolved in the face of potential gene flow between populations. We suggest that the ‘divergence‐with‐gene‐flow’ model of speciation may account for the diversification of estuarine populations. The approach used can potentially idengify ‘incipient estuarine species’, being relevant to the investigation of the evolutionary relationships of silversides in several coastal regions of the world.
A generalized heterozygote deficiency assessed with microsatellites in French common ash populations
Authors: Morand M.‐E. , Brachet S. , Rossignol P. , Dufour J. , Frascaria‐Lacoste N. 
Published: March 2003

AbstractCommon ash is a temperate forest tree with a colonizing behaviour, a discontinuous spatial distribution and a peculiar and poorly known mating system. Microsatellite markers were used to study the genetic structure in natural populations of common ash. Twelve populations located in northeastern France were analysed at five loci. Levels of genetic variability within and among stands were estimated for the seedling and adult stages. As expected for a forest tree, our results reveal high levels of intrapopulation diversity and a low genetic differentiation between stands. However, a general and significant heterozygote deficiency was found, with a mean FIS of 0.163 for the seedlings and of 0.292 for the adult trees. The different explanations for such an excess homozygosity are discussed: a nonMendelian inheritance of alleles, the presence of null alleles, a Wahlund effect and assortative mating.