bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic variation among interconnected populations of Catostomus occidentalis: implications for distinguishing impacts of contaminants from biogeographical structuring
Authors: Whitehead Andrew , Anderson Susan L. , Kuivila Kathryn M. , L. Roach Jennifer , May Bernie 
Published: September 2003

AbstractExposure to contaminants can affect survivorship, recruitment, reproductive success, mutation rates and migration, and may play a significant role in the partitioning of genetic variation among exposed and nonexposed populations. However, the application of molecular population genetic data to evaluate such influences has been uncommon and often flawed. We tested whether patterns of genetic variation among native fish populations (Sacramento sucker, Catostomus occidentalis) in the Central Valley of California were consistent with long‐term pesticide exposure history, or primarily with expectations based on biogeography. Field sampling was designed to rigorously test for both geographical and contamination influences. Fine‐scale structure of these interconnected populations was detected with both amplified fragment length polymorphisms (AFLP) and microsatellite markers, and patterns of variation elucidated by the two marker systems were highly concordant. Analyses indicated that biogeographical hypotheses described the data set better than hypotheses relating to common historical pesticide exposure. Downstream populations had higher genetic diversity than upstream populations, regardless of exposure history, and genetic distances showed that populations from the same river system tended to cluster together. Relatedness among populations reflected primarily directions of gene flow, rather than convergence among contaminant‐exposed populations. Watershed geography accounted for significant partitioning of genetic variation among populations, whereas contaminant exposure history did not. Genetic patterns indicating contaminant‐induced selection, increased mutation rates or recent bottlenecks were weak or absent. We stress the importance of testing contaminant‐induced genetic change hypotheses within a biogeographical context. Strategic application of molecular markers for analysis of fine‐scale structure, and for evaluating contaminant impacts on gene pools, is discussed.
Chloroplast DNA diversity of the dioecious European tree Ilex aquifolium L. (English holly)
Authors: Rendell S. , Ennos R. A. 
Published: September 2003

AbstractVariation in the chloroplast genome of Ilex aquifolium (English holly), a dioecious evergreen tree native to south, west and central Europe, was analysed using polymerase chain reaction–restriction fragment length polymorphisms (PCR‐RFLPs) and microsatellites. Differentiation between populations was high (GST = 0.595) and evidence for phylogeographical structure was detected (NST = 0.697, significantly higher than GST). Two chloroplast lineages were inferred originating from putative glacial refugia in southern Europe (Iberia, Italy and possibly the Balkans). The GST value was higher than reported for endozoochorous hermaphrodite species and for anemochorous dioecious species investigated over a similar geographical scale. It appears that dioecy has contributed to strong differentiation between refugia and that this has been maintained following postglacial recolonization as a result of limited seed flow. Palynological records for I. aquifolium are poor, thus these results give an important insight into patterns of glacial isolation and postglacial recolonization of this species.
Postglacial population growth of Cunninghamia konishii (Cupressaceae) inferred from phylogeographical and mismatch analysis of chloroplast DNA variation
Authors: Hwang Shih‐Ying , Lin Tsan‐Piao , Ma Chiu‐Shun , Lin Chung‐Ling , Jeng‐Der Chung  , Yang Jenq‐Chuan 
Published: September 2003

AbstractPhylogeographical and mismatch analysis of chloroplast DNA (cpDNA) variation were used to infer the temporal dynamics of distributional and demographic history of Taiwan fir (Cunninghamia konishii). We examined 64 and 52 trees from 17 populations of C. konishii and 14 provenances of C. lanceolata, respectively, by sequencing three intergenic spacers and one intron using cpDNA universal primers. Of the aligned 1888 base pairs (bp) sequence, 30 varied among 28 haplotypes, which consisted of three transitions, 14 transversions and 13 indels. One ancestral haplotype was found in 86 individuals across the surveyed range of both species, C. konishii and C. lanceolata, which was distributed in all populations and provenances. The 28 haplotypes also included 15 C. konishii specific and 12 C. lanceolata‐specific haplotypes. Ancestral haplotype was found fixed in five populations of C. konishii and five provenances of C. lanceolata. Other haplotypes occurred mainly as singletons. The levels of population differentiation studied are relatively low in both Cunninghamia species. The nucleotide diversity (θ) of chloroplast DNA sequences within C. konishii was slightly higher than that of C. lanceolata. Excess in singletons as well as star‐like phylogeny of haplotypes suggested no clearcut migration patterns of C. konishii after glacial maximum. One probable demographic history of C. konishii is the postglacial population growth of C. konishii after a glacial bottleneck event. This inference is supported by the combined results of fossil pollen record, low nucleotide diversity, significant Tajima's d‐value, phylogeographical analysis and unimodal mismatch distribution. Similarities and discrepancies between our results and those of Lu et al. (2001) are discussed.
Population subdivision in westslope cutthroat trout (Oncorhynchus clarki lewisi) at the northern periphery of its range: evolutionary inferences and conservation implications
Authors: Taylor E. B. , Stamford M. D. , Baxter J. S. 
Published: September 2003

AbstractWestslope cutthroat trout (Oncorhynchus clarki lewisi, Salmonidae) are native to the upper Columbia, Missouri, and South Saskatchewan river drainages of western North America and are at the northern periphery of their range in southeastern British Columbia, Canada. We examined geographical variation in allele frequencies at eight microsatellite loci in 36 samples of westslope cutthroat trout from British Columbia to assess levels of population subdivision and to test the hypothesis that different habitat types (principally mainstem vs. above migration barrier habitats) would influence levels of genetic diversity, genetic divergence among populations, and attainment of equilibrium between gene flow and genetic drift. Across all samples, the mean number of alleles per locus was 3.9 and mean expected heterozygosity was 0.56. Population subdivision was extensive with an overallFst(θ) of 0.32. Populations sampled above migration barriers had significantly fewer alleles, lower expected heterozygosity, but greater average pairwiseFstthan populations sampled from mainstem localities. We found evidence for isolation‐by‐distance from a significant correlation between genetic distance and geographical distance (r = 0.31), but the pattern was much stronger (r = 0.51) when above barrier populations and a population that may have been involved in headwater exchanges were removed. By contrast, isolation‐by‐distance was not observed when only above barrier populations were tested among themselves. Our data support the maintenance of separate demographic management strategies for westslope cutthroat trout inhabiting different river systems and illustrate how differing habitat structure (e.g. presence of migration barriers) may influence patterns of biodiversity and gene flow‐drift equilibrium.
Colony and population genetic structure of the Formosan subterranean termite, Coptotermes formosanus, in Japan
Authors: Vargo Edward L. , Husseneder Claudia , Grace J. Kenneth 
Published: September 2003

AbstractSubterranean termites have unusual plasticity in their breeding systems. As a result of their cryptic foraging and nesting habits, detailed information on the numbers and types of reproductive individuals in colonies has been difficult to obtain. In this study, we used microsatellite markers to infer the major features of the breeding system of the Formosan subterranean termite, Coptotermes formosanus, in southern Japan, where it is believed to have been introduced from China. A total of 30 colonies was sampled from two islands (Kyushu and Fukue) located 100 km apart. Twenty workers from each colony were genotyped at six microsatellite loci. Analysis of worker genotypes within colonies indicated that 27 colonies (90%) were simple (Mendelian) families. The remaining three colonies, all from Kyushu, were consistent with being extended families having begun as simple families but being currently headed by multiple neotenic (secondary) reproductives descended from the original king and queen. Workers from simple families in both populations were significantly inbred (FIT = 0.10 for Kyushu and 0.46 for Fukue) and highly related to their nestmates (coefficient of relatedness, r = 0.59 for Kyushu and 0.77 for Fukue), suggesting that many simple‐family colonies were headed by closely related reproductives, especially in the Fukue population. This conclusion is supported by the high coefficient of relatedness between nestmate reproductives in simple‐family colonies (r = 0.23 for Kyushu and 0.61 for Fukue) based on genotypes inferred from their worker offspring. There was moderate genetic differentiation (FST = 0.12) between the two populations, suggesting rather restricted gene flow between them. There was no significant isolation by distance among colonies, as might be expected given the limited dispersal of reproductives, presumably because of the frequent movement of colonies by humans. Finally, there was no evidence of a recent bottleneck, a finding possibly consistent with the more than 300‐year history of this species in Japan.
Genetic distinction of wildcat (Felis silvestris) populations in Europe, and hybridization with domestic cats in Hungary
Authors: Pierpaoli M. , Birò Z. S. , Herrmann M. , Hupe K. , Fernandes M. , Ragni B. , Szemethy L. , Randi E. 
Published: September 2003

AbstractThe genetic integrity and evolutionary persistence of declining wildcat populations are threatened by crossbreeding with widespread free‐living domestic cats. Here we use allelic variation at 12 microsatellite loci to describe genetic variation in 336 cats sampled from nine European countries. Cats were identified as European wildcats (Felis silvestris silvestris), Sardinian wildcats (F. s. libyca) and domestic cats (F. s. catus), according to phenotypic traits, geographical locations and independently of any genetic information. Genetic variability was significantly partitioned among taxonomic groups (FST = 0.11; RST = 0.41; P < 0.001) and sampling locations (FST = 0.07; RST = 0.06; P < 0.001), suggesting that wild and domestic cats are subdivided into distinct gene pools in Europe. Multivariate and Bayesian clustering of individual genotypes also showed evidence of distinct cat groups, congruent with current taxonomy, and suggesting geographical population structuring. Admixture analyses identified cryptic hybrids among wildcats in Portugal, Italy and Bulgaria, and evidenced instances of extensive hybridization between wild and domestic cats sampled in Hungary. Cats in Hungary include a composite assemblage of variable phenotypes and genotypes, which, as previously documented in Scotland, might originate from long lasting hybridization and introgression. A number of historical, demographic and ecological conditions can lead to extensive crossbreeding between wild and domestic cats, thus threatening the genetic integrity of wildcat populations in Europe.
Phylogeography of the coronulid barnacle, Chelonibia testudinaria, from loggerhead sea turtles, Caretta caretta
Authors: Rawson P. D. , Macnamee R. , Frick M. G. , Williams K. L. 
Published: September 2003

AbstractThe barnacle, Chelonibia testudinaria, is a common inhabitant of the marine turtle epibiont community and plays a key role in the development of this community. Phylogeographic analysis of 79 cytochrome c oxidase I (COX1) sequences for barnacles collected from five populations found contrasting patterns of divergence for populations in the Atlantic vs. the Pacific Ocean. Our analysis indicates that the two Pacific populations, Senri Beach, Japan and Bahia Magdalena, Mexico, were not only highly divergent from the Atlantic populations but are highly divergent from one another. We suggest that barnacles from these populations may represent cryptic species. In contrast, sequence divergence was greatly reduced among barnacles collected from Wassaw Island, GA, USA, Keewaydin, FL, USA, and Kyparissia, Pèloponnésus Island, Greece. A reduction in sequence diversity at the latter site was attributed to a recent range expansion into the Mediterranean Sea. We examined historical patterns of migration among the three Atlantic and Mediterranean populations using the program migrate. This analysis indicates a high rate of migration from Keewaydin to Wassaw Island, contrasted with a much lower rate of migration in the opposite direction. The estimated migration rate from Kyparissia to Keewaydin was also non‐negligible. We suggest that the association between C. testudinaria and loggerhead turtles and the patterns of turtle migration have played key roles in the expansion of the range of C. testudinaria into the Mediterranean Sea and the subsequent patterns of barnacle migration. We further propose that the difference between ocean basins, with respect to the impact of host migration on barnacle gene flow, probably stems from the fact that host‐mediated dispersal in the Atlantic depends on advanced stage juveniles and adults while any host‐mediated dispersal in the Pacific would have to involve early ‘pelagic’ stage juvenile loggerheads.
Cryptic species and morphological plasticity in long‐lived bivalves (Unionoida: Hyriidae) from inland Australia
Authors: Baker Andrew M. , Bartlett Chris , Bunn Stuart E. , Goudkamp Katrina , Sheldon Fran , Hughes Jane M. 
Published: September 2003

AbstractMolecular (mitochondrial DNA, isozyme) and morphological diversity of freshwater mussels (Family Hyriidae) was examined at 21 sites encompassing four large river systems, across southwest Queensland, Australia. Evidence was found for two major morphological groups. One group, which occurred in every river system, closely matched a recognized species (Velesunio ambiguus) both morphologically and in a well‐supported lineage within a mitochondrial phylogeny generated from partial cytochrome c oxidase subunit I (COI) sequences. The second group most closely matched Velesunio wilsonii in shell morphology but formed three deeply divergent mitochondrial DNA lineages. All four lineages occurred sympatrically in some areas and displayed corresponding fixed differences at nuclear allozyme loci, which suggests an absence of recent hybridization and the presence of separate species.
A hybrid zone dominated by fertile F1s: maintenance of species barriers inRhododendron
Authors: Milne R. I. , Terzioglu S. , Abbott R. J. 
Published: September 2003

AbstractIsolating barriers between interbreeding sympatric or parapatric interfertile species are maintained by processes that occur within their hybrid zones. Although the effects of intrinsic selection on hybrid fitness are well known, less is understood about extrinsic fitness variation. At Tiryal Dag, northeast Turkey,Rhododendron×sochadzeae(R. ponticum×caucasicum) forms large populations in which neither segregation nor backcrossing occur, in habitats intermediate between those of its parents. Using single‐copy species‐specific random amplified polymorphic DNA and inter simple sequence repeat markers, it was determined that most or allR.×sochadzeaeplants are F1s, and that there are many separate genets present. Hand pollination and germination experiments showed thatR.×sochadzeaeplants can produce viable seed of F2s or backcrosses in either direction. Furthermore, adult backcrosses have been observed in habitats atypical forR.×sochadzeae. From this, all non‐F1hybrid derivatives appear to be eliminated in the hybrid zone at Tiryal Dag as a result of postgermination selection. This absence of post‐F1hybrid derivatives apparently prevents introgression. This type of hybrid population is here termed an F1‐dominated hybrid zone (F1DZ), and also occurs inEncelia. The observed dominance of F1s within a narrow habitat range is best explained by habitat‐mediated superiority of F1s over all other genotype classes. Therefore, habitat‐mediated selection against the second hybrid generation might be preventing interspecific gene flow inR.×sochadzeae. F1DZ formation is postulated to require the formation of F1s in quantity, habitat‐mediated superiority in F1s, and highly specific habitat conditions.
Ecological and morphological differentiation among cryptic evolutionary lineages in freshwater limpets of the nominal form‐group Ancylus fluviatilis (O.F. Müller, 1774)
Authors: Pfenninger Markus , Staubach Sid , Albrecht Christian , Streit Bruno , Schwenk Klaus 
Published: September 2003

AbstractThe phylogeny and potential mode of speciation of the river limpet Ancylus fluviatilis (Basommatophora) was examined using mitochondrial DNA sequences from 16S ribosomal RNA, cytochrome c oxidase subunit I (COI) and nuclear DNA from internal transcribed spacer (ITS‐1) regions from 103 populations across Europe. Four highly divergent lineages were observed within Ancylus. Clade 1, representing the nominal taxon Ancylus fluviatilis (O.F. Müller, 1774), is mainly found in central and northern Europe, Clade 2 is present in a single Portuguese population, Clade 3 is distributed on the Canary islands, North Africa and the eastern Mediterranean region, whereas Clade 4 inhabits the Northern Mediterranean coasts. Phylogenetic analyses revealed an overall consistent topology of nuclear and mitochondrial gene trees. Based on a molecular clock, we estimated that the basic radiation occurred in the late Pliocene. Although clades differ significantly in size independent shell shape, morphological differentiation of lineages is not feasible without genetic data. Environmental data related to climate (precipitation, temperature, etc.) showed a significant differentiation of clades. Clade 1 dwells in relatively colder and more stable habitats than Clades 3 and 4, whose habitats in turn differ in a low or high amount of precipitation during spring and autumn, respectively. Based on the combined data sets on mitochondrial DNA, nuclear DNA, morphological and ecological differentiation, we conclude that Ancylus represents a cryptic species complex of reproductively and genetically isolated lineages. In addition, the joint analysis suggests that ecological speciation is probable to explain current patterns.
Phylogeography of shy and white‐capped albatrosses inferred from mitochondrial DNA sequences: implications for population history and taxonomy
Authors: Abbott Cathryn L. , Double Michael C. 
Published: September 2003

AbstractThe evolutionary relationship between shy (Thalassarche cauta) and white‐capped (T. steadi) albatrosses was examined using mitochondrial control region sequences. Results were interpreted in the context of a recent and contentious taxonomic revision that recommended full species status for shy and white‐capped albatrosses. Low sequence divergence between shy and white‐capped albatrosses (1.8%) and between their close relatives, Salvin's and Chatham albatrosses (2.9%), was observed. Much higher sequence divergence was found between the shy/white‐capped pair and the Salvin’s/Chatham pair (7.0%). Phylogenetic analyses confirmed the separation of the shy/white‐capped pair from the Salvin’s/Chatham pair but did not provide species‐level resolution. Phylogeographic analyses, including a nested clade analysis, FST estimates and an analysis of molecular variance, indicated unambiguous genetic structuring between shy and white‐capped albatrosses, thus confirming the demographic isolation of the species, but showed little to no structuring within each species. The geographical distribution of mtDNA haplotypes and other evidence suggest that shy albatrosses arose through range expansion by white‐capped albatrosses.
Genetic and behavioural estimates of reproductive skew in male fallow deer
Authors: Say L. , Naulty F. , Hayden T. J. 
Published: September 2003

AbstractPopulations of fallow deer, in general, have low genetic diversity. Nevertheless, we screened 39 microsatellite loci and identified 20 that were polymorphic and suitable to determine paternity of fallow deer. To date, paternity has been studied for 87, 110 and 152 fallow deer fawns born between 2000 and 2002. Our results confirm the existence of a strong polygynous mating system in our population and confirm that the number of copulations performed by males is globally a good estimator of their reproductive success: males which performed the largest proportion of matings fathered the largest proportion of fawns. Nevertheless, we report some differences between the two measurements of the males’ reproductive success: measures of copulatory success underestimated the variance of the males’ reproductive success. On average, males whose copulatory score exceeded their paternity had mated with a higher proportion of younger females. Young females may be more likely to lose the conceptus, or their offspring may suffer high postnatal mortality.
Coevolution between slave‐making ants and their hosts: host specificity and geographical variation
Authors: Blatrix R. , Herbers J. M. 
Published: September 2003

AbstractWe explored the impact of a slave‐making ant, Protomognathus americanus, on two of its hosts, Leptothorax longispinosus and L. ambiguus. We showed that, on average, slave‐maker colonies conduct raids on 2.7 L. longispinosus and 1.4 L. ambiguus nests in a single year. The more common host, L. longispinosus, survives raiding and colony‐founding events in a third of the cases, but the less common host rarely survives attacks from the slave‐makers. We compare our results, collected in Vermont, to a study conducted in New York where the slave‐maker pressure is much stronger. Our results suggest that in Vermont the slave‐maker has a sparing strategy when raiding L. longispinosus, but not when raiding L. ambiguus. Thus coevolution between slave‐making ants and their hosts shows host specificity and geographical variation.
Mitochondrial DNA sequences reveal extensive cryptic diversity within a western American springsnail
Authors: Liu Hsiu‐Ping , Hershler Robert , Clift Kayla 
Published: September 2003

AbstractWe analysed cytochrome c oxidase subunit I and NADH dehydrogenase subunit I sequence variation among 29 populations of a widely ranging southwestern springsnail (Pyrgulopsis micrococcus) and 18 regional congeners. Cladistic analyses of these sequences depict P. micrococcus as a polyphyletic composite of five well‐supported clades. Sequence divergences among these clades and subclades imply the possible occurrence of as many as seven or eight cryptic species in addition to P. micrococcus. Our finding that P. micrococcus contains multiple, genetically distinct and geographically restricted lineages suggests that diversification within this highly speciose aquatic genus has been structured in large part by the operation of terrestrial barriers to gene flow. However, these sequence data also indicate that recent dispersal among hydrographically separated areas has occurred within one of these lineages, which we attribute to passive transport on migratory waterbirds.