bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic relatedness and female spatial organization in a solitary carnivore, the raccoon, Procyon lotor
Authors: Ratnayeke Shyamala , Tuskan Gerald A. , Pelton Michael R. 
Published: March 2003

AbstractAmong mammals, some of the most common types of cohesive social groupings originate from natal philopatry through the extended mother family. This retention of females within social groups (i.e. the nonrandom dispersion of female relatives in space) should affect population genetic structure. We examined the relationship between genetic relatedness and female spatial organization in a wild population of the North‐American raccoon, Procyon lotor, a solitary carnivore in east Tennessee. Multilocus genetic band‐sharing data and 3½ years of radiotelemetry observations were used to study the spatial and genetic relationships among 38 adult females. DNA amplification employing primers of arbitrary sequence (random amplified polymorphic DNA; RAPD) indicated that female philopatry in raccoons led to a greater likelihood of neighbours being more related than expected by chance. Genetic distance based on RAPD band frequency was positively correlated with spatial distance among females (P = 0.0001) and genetic similarity was positively correlated with the extent of home‐range overlap (P = 0.0028). Philopatry seemed biased towards females; average female–female similarities were greater than average male–male similarities (P = 0.0001), or average male–female similarities (P = 0.0001). High home‐range overlap among some females with low or moderate levels of band sharing indicated that maternal inheritance of space was not a prerequisite for establishing or sharing home ranges. Female philopatry was the most probable explanation for the nonrandom spatial and genetic association of raccoons in east Tennessee.
Reproductive mode and genetic variation suggest a North American origin of European Letharia vulpina
Authors: Högberg Nils , Kroken Scott , Thor Göran , Taylor John W. 
Published: March 2003

AbstractOur data on the intercontinental population biology of Letharia vulpina show an unexpected shift from a recombining North American population with unique haplotypes to genetically depauperate Swedish and Italian populations, each with many representatives of a single repeated haplotype. Analysis of eight loci in 47 individuals supported recombination in North American populations and showed almost no variation among European populations. We infer that a genetic bottleneck caused by limited long‐distance dispersal accounts for the lack of genetic variation found in marginal populations. This lack of variation in the European populations makes it impossible to use population genetic means to distinguish clonal reproduction from self‐fertilization or even outcrossing, but phenotype indicates that reproduction in the marginal populations is by clonal spread, via soredia and isidioid soredia.
Sampling within the genome for measuring within‐population diversity: trade‐offs between markers
Authors: Mariette S. , Le Corre V. , Austerlitz F. , Kremer A. 
Published: March 2003

AbstractExperimental results of diversity estimates in a set of populations often exhibit contradictory patterns when different marker systems are used. Using simulations we identified potential causes for these discrepancies. These investigations aimed also to detect whether different sampling strategies of markers within the genome resulted in different estimates of the diversity at the whole genome level. The simulations consisted in generating a set of populations undergoing various evolutionary scenarios which differed by population size, migration rate and heterogeneity of gene flow. Population diversity was then computed for the whole genome and for subsets of loci corresponding to different marker techniques. Rank correlation between the two measures of diversity were investigated under different scenarios. We showed that the heterogeneity of genetic diversity either between loci (genomic heterogeneity, GH) or among populations (population heterogeneity, PH) varied greatly according to the evolutionary scenario considered. Furthermore, GH and PH were major determinants of the level of rank correlation between estimates of genetic diversities obtained using different kinds of markers. We found a strong positive relationship between the level of the correlation and PH, whatever the marker system. It was also shown that, when GH values were constantly low during generations, a reduced number of microsatellites was enough to predict the diversity of the whole genome, whereas when GH increased, more loci were needed to predict the diversity and amplified fragment length polymorphism markers would be more recommended in this case. Finally the results are discussed to recommend strategies for gene diversity surveys.
Evolutionary and statistical properties of three genetic distances
Authors: Kalinowski Steven T. 
Published: March 2003

AbstractMany genetic distances have been developed to summarize allele frequency differences between populations. I review the evolutionary and statistical properties of three popular genetic distances:DS,DA, and θ, using computer simulation of two simple evolutionary histories: an isolation model of population divergence and an equilibrium migration model. The effect of effective population size, mutation rate, and mutation mechanism upon the parametric value between pairs of populations in these models explored, and the unique properties of each distance are described. The effect of these evolutionary parameters on study design is also investigated and similar results are found for each genetic distance in each model of evolution: large sample sizes are warranted when populations are relatively genetically similar; and loci with more alleles produce better estimates of genetic distance.
Speciation in fig pollinators and parasites
Authors: Weiblen George D. , Bush Guy L. 
Published: March 2003

AbstractHere we draw on phylogenies of figs and fig wasps to suggest how modes of speciation may be affected by interspecific interactions. Mutualists appear to have cospeciated with their hosts to a greater extent than parasites, which showed evidence of host shifting. However, we also repeatedly encountered a pattern not explained by either cospeciation or host switching. Sister species of fig parasites often attack the same host in sympatry, and differences in ovipositor length suggest that parasite speciation could result from divergence in the timing of oviposition with respect to fig development. These observations on fig parasites are consistent with a neglected model of sympatric speciation.
Phylogeographical approaches to assessing demographic connectivity between breeding and overwintering regions in a Nearctic−Neotropical warbler (Wilsonia pusilla)
Authors: Kimura M. , Clegg S. M. , Lovette I. J. , Holder K. R. , Girman D. J. , Milá B. , Wade P. , Smith T. B. 
Published: March 2003

AbstractWe characterized the pattern and magnitude of phylogeographical variation among breeding populations of a long‐distance migratory bird, the Wilson's warbler (Wilsonia pusilla), and used this information to assess the utility of mtDNA markers for assaying demographic connectivity between breeding and overwintering regions. We found a complex pattern of population differentiation in mitochondrial DNA (mtDNA) variation among populations across the breeding range. Individuals from eastern North America were differentiated from western individuals and the eastern haplotypes formed a distinct, well‐supported cluster. The more diverse western group contained haplotype clusters with significant geographical structuring, but there was also broad mixing of haplotype groups such that no haplotype groups were population specific and the predominance of rare haplotypes limited the utility of frequency‐based assignment techniques. Nonetheless, the existence of geographically diagnosable eastern vs. western haplotypes enabled us to characterize the distribution of these two groups across 14 overwintering locations. Western haplotypes were present at much higher frequencies than eastern haplotypes at most overwintering sites. Application of this mtDNA‐based method of linking breeding and overwintering populations on a finer geographical scale was precluded by the absence of population‐specific markers and by insufficient haplotype sorting among western breeding populations. Our results suggest that because migratory species such as the Wilson's warbler likely experienced extensive gene flow among regional breeding populations, molecular markers will have the greatest utility for characterizing breeding−overwintering connectivity at a broad geographical scale.
Microsatellite DNA evidence for genetic drift and philopatry in Svalbard reindeer
Authors: Côté S. D. , Dallas J. F. , Marshall F. , Irvine R. J. , Langvatn R. , Albon S. D. 
Published: March 2003

AbstractMainland populations of Arctic reindeer and caribou Rangifer tarandus often undergo extensive movements, whereas populations on islands tend to be isolated and sedentary. To characterize the genetic consequences of this difference, levels of genetic diversity and subdivision of Svalbard reindeer (R. t. platyrhynchus) from two adjacent areas on Nordenskjiöldland, Spitsbergen were estimated using data from up to 14 microsatellites. The mean number of alleles per locus in Svalbard reindeer was 2.4 and mean expected heterozygosity per locus was 0.36. The latter value was significantly lower than in Canadian caribou and Norwegian reindeer but higher than in some other cervid species. Large samples of females (n = 743) and small samples of males (n = 38) from two sites ≈ 45 km apart showed genetic subdivision, which could be due to local population fluctuations or limited gene flow. To our knowledge, this is the first study to report significant differentiation at microsatellite loci in Rangifer at such short geographical distances. Neither population showed genetic evidence for recent population bottlenecks when loci unbiased with respect to heterozygosity were analysed. In contrast, false signals of a recent bottleneck were detected when loci upwardly biased with respect to heterozygosity were analysed. Thus, Svalbard reindeer appeared to conform to the paradigm of island populations made genetically depauperate by genetic drift.
Paternity frequency and maternity of males in some stingless bee species
Authors: Palmer Kellie A. , Oldroyd Benjamin P. , Quezada‐Euán José Javier G. , Paxton Robert J. , May‐Itza William De J. 
Published: March 2003

AbstractIn monogynous hymenopteran societies, the number of mates of a queen strongly influences the potential for conflict between workers and queens over the maternity of males. Queens always ‘prefer’ their own sons to sons of workers, regardless of queen mating frequency. When a queen mates once, workers are more closely related to, and therefore are expected to prefer, their own sons and then sons of sisters to sons of the queen. However, if effective paternity frequency exceeds 2, workers on average should prefer queen‐produced males to males produced by their sisters. We studied the queen mating frequency of seven stingless bee species: the Mexican speciesScaptotrigona mexicana,S. pectoralisand the Australian speciesAustroplebeia symei,Trigona clypearis,T. hockingsi,T. mellipesandT. sapiens. We then determined whether males arise from eggs laid by workers or queens inA. symei,T. clypearis,T. hockingsiandT. mellipes. We show that all seven species investigated are most likely singly mated and that the queen dominates reproduction. This indicates that the queen's mating frequency alone does not determine whether workers or the queen produces the males.
Mitochondrial DNA variation in Pleistocene and modern Atlantic salmon from the Iberian glacial refugium
Authors: Consuegra S. , García De Leániz C. , Serdio A. , González Morales M. , Straus L. G. , Knox D. , Verspoor E. 
Published: March 2003

AbstractCurrent understanding of the postglacial colonization of Nearctic and Palearctic species relies heavily on inferences drawn from the phylogeographic analysis of contemporary generic variants. Modern postglacial populations are supposed to be representative of their Pleistocene ancestors, and their current distribution is assumed to reflect the different colonization success and dispersal patterns of refugial lineages. Yet, testing of phylogeographic models against ancestral genomes from glacial refugia has rarely been possible. Here we compare ND1 mitochondrial DNA variation in late Pleistocene (16 000–40 000 years before present), historical and contemporary Atlantic salmon (Salmo salar) populations from northern Spain and other regions of western Europe. Our study demonstrates the presence of Atlantic salmon in the Iberian glacial refugium during the last 40 000 years and points to the Iberian Peninsula as the likely source of the most common haplotype within the Atlantic lineage in Europe. However, our findings also suggest that there may have been significant changes in the genetic structure of the Iberian refugial stock since the last ice age, and question whether modern populations in refugial areas are representative of ice age populations. A common haplotype that persisted in the Iberian Peninsula during the Pleistocene last glacial maximum is now extremely rare or absent from European rivers, highlighting the need for caution when making phylogeographic inferences about the origin and distribution of modern genetic types.
Extra pair paternity in birds: a review of interspecific variation and adaptive function
Authors: Griffith Simon C. , Owens Ian P. F. , Thuman Katherine A. 
Published: March 2003

AbstractThe application of molecular genetic techniques has revolutionized our view of avian mating systems. Contrary to prior expectations, birds are only very rarely sexually monogamous, with ‘extra‐pair offspring’ found in approximately 90% of species. Even among socially monogamous species, over 11% of offspring are, on average, the result of extra‐pair paternity (EPP). Based on over 150 molecular genetic studies of EPP in birds, we review two topical areas: (i) ecological explanations for interspecific variation in the rate of EPP; and (ii) evidence bearing on the adaptive function of EPP. We highlight the remaining challenges of understanding the relative roles of genes and ecology in determining variation between taxa in the rate of extra paternity, and testing for differences between extra‐pair offspring and those sired within‐pair.
Geographic pattern of genetic variation in the European globeflowerTrollius europaeusL. (Ranunculaceae) inferred from amplified fragment length polymorphism markers
Authors: Despres Laurence , Loriot Sandrine , Gaudeul Myriam 
Published: March 2003

AbstractThe distribution of genetic variation and the phylogenetic relationships between 18 populations of the arctic‐alpine plantTrollius europaeuswere analysed in three main regions (Alps, Pyrenees and Fennoscandia) by using dominant AFLP markers. Analysis of molecular variance revealed that most of the genetic variability was found within populations (64%), although variation among regions (17%) and among populations within regions (19%) was highly significant (P < 0.001). Accordingly, the global fixation indexFSTaveraged over loci was high (0.39). The among‐population differentiation indicates restricted gene flow, congruent with limited dispersal of specific globeflower's pollinating flies (Chiastochetaspp.). Within‐population diversity levels were significantly higher in the Alps (mean Nei's expected heterozygosityHE = 0.229) than in the Pyrenees (HE= 0.197) or in Fennoscandia (HE = 0.158). This finding is congruent with the species‐richness of the associated flies, which is maximum in the Alps. We discuss the processes involved in shaping observed patterns of genetic diversity within and amongT. europaeuspopulations. Genetic drift is the major factor acting on the small Pyrenean populations at the southern edge ofT. europaeusdistribution, while large Fennoscandian populations result probably from a founder effect followed by demographic expansion. The Alpine populations represent moderately fragmented relics of large southern ancestral populations. The patterns of genetic variability observed in the host plant support the hypothesis of sympatric speciation in associated flies, rather than recurrent allopatric speciations.
Metapopulation structure of the specialized herbivoreMacrosiphoniella tanacetaria(Homoptera, Aphididae)
Authors: Massonnet Blandine , Simon Jean‐Christophe , Weisser Wolfgang W. 
Published: March 2003

AbstractWe investigated population dynamics, genetic diversity and spatial structure in the aphid speciesMacrosiphoniella tanacetaria, a specialist herbivore feeding on tansy,Tanacetum vulgare. Tansy plants (genets) consist of many shoots (ramets), and genets are grouped in sites. Thus, aphids feeding on tansy can cluster at the level of ramets, genets and sites. We studied aphid population dynamics in 1997 and 2001 and found that within sites: (i) at any time, aphids used only a fraction of the available ramets and genets; (ii) at the level of ramets, most aphid colonies survived only one week; (iii) at the level of genets, mean survival time was less than 4 weeks; and (iv) colonization and extinction events occurred throughout the season. We sampled aphids in seven sites in the Alsace region, France (4–45 km apart) and two sites in Germany in 1999 to study genetic structure within and between populations. Genetic analyses using nine microsatellite loci showed that: (i) genotypic variability was high, (ii) none of the populations was in Hardy–Weinberg equilibrium, (iii) heterozygote deficits and linkage disequilibria were frequent, and (iv) all populations were genetically differentiated, even at a small geographical scale. Renewed sampling of the Alsace sites in 2001 showed that three populations had become extinct and significant genetic changes had occurred in the remaining four populations. The frequencies of extinction and colonization events at several spatial scales suggest a hierarchical metapopulation structure forM. tanacetaria.Frequent population turnover and drift are likely causes for the genetic differentiation ofM. tanacetariapopulations.
Phylogeography of the invasive cyanobacterium Cylindrospermopsis raciborskii
Authors: Neilan B. A. , Saker M. L. , Fastner J. , Törökné A. , Burns B. P. 
Published: March 2003

Abstract Cylindrospermopsis raciborskii is a planktonic freshwater cyanobacterium that has become increasingly prevalent in tropical and temperate water bodies world‐wide. This species is of concern from a water‐quality perspective because of its known ability to produce toxins that can affect the health of humans and other animals. This study investigates genetic vari‐ation between strains of C. raciborskii isolated from freshwater rivers and reservoirs in Australia, Brazil, Germany, Hungary, Portugal and the USA. Strains were first characterized by analysis of their 16S rRNA gene nucleotide sequences and were found to have a sequence divergence of 99.1%. A phylogenetic tree, constructed using the 16S rRNA gene sequences showed that strains grouped into Australian, European and North/South American phylotypes. To investigate further the observed separation of strains into geographically distinct groups, we applied a cyanobacterium‐specific short tandem repeat sequence technique, HIP1. An electrophoretic comparison of the HIP1 polymerase chain reaction products showed clear distinctions between the C. raciborskii strains. A phylogenetic tree, based on the repeat element banding patterns, also revealed three distinct groups of C. raciborskii strains. The first group consisted of strains from the USA and Brazil; the second comprised European strains from Germany, Hungary and Portugal; and the third were strains from Australia. In general, between‐country variation was greater than within‐country variation, indicating that this fingerprinting technique can successfully distinguish C. raciborskii strains taken from different global locations. The relationship between toxicity and the observed HIP1 polymerase chain reaction fingerprint profiles was less clear, although it is interesting to note that of the strains analysed in this study, only Australian strains are known to produce cylindrospermopsin and only Brazilian strains have been reported to produce paralytic shellfish poisoning toxins.
Possible causes of morphological variation in an endemic Moroccan groundsel (Senecio leucanthemifoliusvar.casablancae): evidence from chloroplast DNA and random amplified polymorphic DNA markers
Authors: Coleman Max , Abbott Richard J. 
Published: March 2003

AbstractGenetic variation was assessed inSenecio leucanthemifoliusvar.casablancae(Compositae), a Moroccan Atlantic coast endemic, in order to examine possible causes of atypical leaf morphology in three populations south of the known range. Evidence for introgression fromS. glaucusssp.coronopifoliusand/or divergence was investigated with molecular markers. Both random amplified polymorphic DNA (RAPD) and chloroplast (cp) DNA restriction fragment length polymorphism (RFLP) differentiated the species well. Some evidence that hybridization may have occurred between the two species was provided by cpDNA markers. However, biparentally inherited RAPD markers failed to provide any support for the hypothesis that intermediate leaf morphologies in atypical populations arose through hybridization. Consequently, they are most likely to have arisen via divergence caused by drift and/or selection. Genetic distances among populations ofS. leucanthemifoliuswere significant in all but one case. Isolation by distance was indicated by a significant positive correlation between genetic and geographical distances (r = 0.68,P = 0.01, Mantel test). These results suggest that long‐distance achene dispersal is rare, despite the presence of a well‐developed pappus. The observed loss of pappus at achene maturity may explain this unexpected result. Due to the morphological distinction of var.casablancaefrom other varieties ofS. leucanthemifolius, we suggest elevation to species rank and treatment of the atypical material at infraspecific rank.