Home About us Contact
|
Home About us Contact | ||
|
|
||
Polymorphic Microsatellite Loci (polymorphic + microsatellite_locus)
Kinds of Polymorphic Microsatellite Loci Selected AbstractsPolymorphic microsatellite loci for the swarm-founding wasp Polybia paulista (Hymenoptera: Vespidae)ENTOMOLOGICAL SCIENCE, Issue 1 2005Kazuyuki KUDÔ Abstract A polymorphic microsatellite locus was isolated and characterized from Polybia paulista, one of the most common polygynic, swarm-founding social wasps in Brazil. Three other microsatellite loci for which the primer sets were originally developed in independent-founding paper wasps also showed polymorphism in the size of amplification products in P. paulista. [source] Polymorphic microsatellite loci for primitively eusocial wasp Ropalidia marginataMOLECULAR ECOLOGY RESOURCES, Issue 4 2009S. JOHNY Abstract We report here development and characterization of 48 novel microsatellite markers for Ropalidia marginata, a tropical, primitively eusocial polistine wasp from peninsular India. Thirty-two microsatellites showed polymorphism in a wild population of R. marginata (N = 38) collected from Bangalore, India. These markers will facilitate answering some interesting questions in ecology and evolutionary biology of this wasp, such as population structure, serial polygyny, intra-colony genetic relatedness and the pattern of queen succession. [source] Polymorphic microsatellite loci in the widespread amphidromous goby Sicyopterus lagocephalus and cross-genus amplification among SicydiinaeMOLECULAR ECOLOGY RESOURCES, Issue 2 2009T. B. HOAREAU Abstract Microsatellite DNA markers were isolated in an amphidromous goby (Sicyopterus lagocephalus) from a partial genomic library enriched for AC repeats. Eight microsatellites were highly polymorphic with six to 33 alleles per locus and expected heterozygosities ranging from 0.53 to 0.97. Cross-species amplifications were performed within the sub-family Sicydiinae by genotyping individuals from two species of the genus Cotylopus. Some of these loci were successfully amplified and showed polymorphism in the second genus. [source] Polymorphic microsatellite loci from northern and Mexican corn rootworms (Insecta: Coleoptera: Chrysomelidae) and cross-amplification with other Diabrotica spp.MOLECULAR ECOLOGY RESOURCES, Issue 3 2008ERIC R. WAITS Abstract The northern corn rootworm (Diabrotica barberi) and Mexican corn rootworm (Diabrotica virgifera zeae) are significant agricultural pests. For the northern corn rootworm, and to a lesser extent, the Mexican corn rootworm, high resolution molecular markers are needed. Here we present 14 polymorphic microsatellite loci isolated from libraries constructed using pooled northern and Mexican corn rootworm genomic DNA. Polymorphism in other Diabrotica, including the banded cucumber beetle, southern corn rootworm and western corn rootworm, is described. [source] Polymorphic microsatellite loci in Linum usitatissimumMOLECULAR ECOLOGY RESOURCES, Issue 3 2006C. ROOSE-AMSALEG Abstract We report the characterization of 28 polymorphic microsatellite markers in Linum usitatissimum that allow distinguishing almost all cultivars of both flax and linseed. Polymorphism was low, ranging from two to 10 alleles per locus in the 93 cultivars screened. Linkage disequilibrium was found at about a third of the pairs of loci likely due to self-fertilization and strong selection by breeders. We tested these loci for cross-amplification in nine additional species of Linum and found that three species amplified a majority of loci. [source] Polymorphic microsatellite loci for the trematode Diplostomum pseudospathaceumMOLECULAR ECOLOGY RESOURCES, Issue 4 2004THORSTEN B. H. REUSCH Abstract We present primers for five polymorphic microsatellite loci in the eye fluke Diplostomum pseudospathaceum (Trematoda), a widely distributed parasite with a complex life cycle used as a model for parasitology and fish immunology. The loci were identified using a GA/CT-enriched genomic library by subtractive hybridization with magnetic particles. All five loci were highly polymorphic, displaying 17 to 61 alleles and heterozygosities ranging from 0.53 to 0.92. We isolated populations of parasites within the first (snail) and second (fish) intermediate host and found small but significant genetic differentiation (FST = 0.012) between the two life stages of the parasite. [source] Polymorphic microsatellite loci in Plantago lanceolataMOLECULAR ECOLOGY RESOURCES, Issue 1 2003Marie L. Hale Abstract The genus Plantago is particularly interesting for evolutionary studies because of its wide range of mating systems. We have developed primers for five highly polymorphic microsatellite loci isolated from P. lanceolata. All five loci amplified and were polymorphic in the two populations examined, Lowsteads Beach in the United Kingdom and Duke in the United States. These new markers will allow a comparison of population structure between the outcrossing species P. lanceolata, and the highly selfing species P. major. [source] Microsatellite DNA loci for Western Hemlock [Tsuga heterophylla (Raf.) Sarg]MOLECULAR ECOLOGY RESOURCES, Issue 3 2002Vindhya Amarasinghe Abstract Polymorphic microsatellite loci were developed for Western Hemlock [Tsuga heterophylla (Raf.) Sarg], a prominent forest tree species in Western North America. Microsatellite-enriched libraries were screened for (CA)n dinucleotide repeats from which 33 positive clones were sequenced. Polymerase chain reaction (PCR) primers for 16 microsatellite loci were prepared and tested against DNA from unrelated Western Hemlock trees. The 12 most informative microsatellite loci are reported here. From four to 22 alleles per locus were observed, with an average expected heterozygousity of 0.799. [source] Polymorphic microsatellite loci from the Southeast Asian cyprinid, Barbodes gonionotus (Bleeker)MOLECULAR ECOLOGY RESOURCES, Issue 2 2002W. Kamonrat Abstract The cyprinid Barbodes gonionotus (Bleeker) is a commercially important fish in both capture fisheries and aquaculture in Southeast Asia. Five polymorphic microsatellite loci from B. gonionotus are described. Four are highly variable, with 9,30 alleles observed per locus in four populations sampled from Thailand (HO = 0.694,0.808). These will be of use in studies of population genetic structure and in pedigree analyses. [source] Polymorphic microsatellite loci for assigning parentage in least flycatchers (Empidonax minimus)MOLECULAR ECOLOGY RESOURCES, Issue 3 2001S. A. Tarof Abstract Least flycatchers (Empidonax minimus) are socially monogamous birds that form tight territorial aggregations on the breeding grounds. We designed five polymorphic microsatellite loci for assigning parentage to offspring within least flycatcher clusters. The number of alleles per locus ranged from 7 to 18. Mean polymorphic information content was 83.8%; the probability of exclusion with known maternal genotype was 0.999. These microsatellites are powerful DNA markers for identifying extra-pair paternity in this species. Preliminary data also suggest that these loci may be useful for other members of this genus. [source] Polymorphic microsatellite loci for the common marmoset (Callithrix jacchus) designed using a cost- and time-efficient methodAMERICAN JOURNAL OF PRIMATOLOGY, Issue 9 2008M. Raveendran Abstract We describe a cost- and time-efficient method for designing new microsatellite markers in any species with substantial genomic DNA sequence data available. Using this technique, we report 14 new polymorphic dinucleotide microsatellite loci isolated from the common marmoset. The relative yield of new polymorphisms was higher with less labor than described in previous marmoset studies. Of 20 loci initially evaluated, 14 were polymorphic and amplified reliably (70% success rate). The number of alleles ranged from 3 to 9 with heterozygosity varying from 0.48 to 0.83. Am. J. Primatol. 70:906,910, 2008. © 2008 Wiley-Liss, Inc. [source] Population structure and its implications for conservation of the great silver beetle Hydrophilus piceus in BritainFRESHWATER BIOLOGY, Issue 11 2007TREVOR J. C. BEEBEE Summary 1. The great silver water beetle Hydrophilus piceus is one of the largest aquatic insects in Europe. In Britain it is rare and endangered, and confined to a small number of low-lying marshes. Very little is known about the beetle populations in any of these areas, or the connectivity between them. 2. To investigate the population structure of H. piceus in Britain, four polymorphic microsatellite loci were identified and characterized. The genome of this beetle seems to have few microsatellites but contains a high proportion of a larger repeated sequence. 3. All six of the main British populations (Somerset, Lewes, Pevensey, Romney, North Kent and Norfolk) showed substantial genetic diversity at the microsatellite loci. However, estimates of effective population size at one site (Pevensey) were remarkably low, at <10 adults for the period 2004,05. 4. Most of the genetic diversity was partitioned within rather than among the populations, although there was, nevertheless, significant genetic sub-structuring. Almost all population pairwise Fst estimates were significantly different from zero, and there was a clear isolation-by-distance effect. Assignment tests and cluster analyses demonstrated interpopulation relationships largely consistent with their geographical separations. 5. Hydrophilus disperses by flight, and records from moth traps indicated that there was no month in which the beetles never flew, but that flight activity was highest in the spring. 6. The genetic data highlight the need to maintain or regenerate habitat connectivity within flying distance for H. piceus, and to sustain large areas of suitable breeding marshes. [source] Physiological response to stress in fledgling Lesser Kestrels Falco naumanni: the role of physical condition, sex and individual genetic diversityIBIS, Issue 3 2009JOAQUÍN ORTEGO Exposure to chronic stress early on during development has important deleterious consequences later in life, reducing important components of individual fitness such as survival and future reproduction. In this study, we evaluate the factors associated with physiological response to stress in fledgling Lesser Kestrels Falco naumanni, paying particular attention to the potential role of individual genetic diversity. For this purpose, we used heterophil/lymphocyte ratios (H/L ratio) as a haematological stress indicator and typed the analysed individuals at 11 highly polymorphic microsatellite loci, which allowed us to estimate their genetic diversity. We found that the H/L ratio decreases with fledgling physical condition, suggesting that this parameter is a good indicator of nutritionally based physiological stress. Physiological response to stress was higher in males than in females and this effect was independent of physical condition, suggesting that the observed pattern is due to inherent sexual differences in the factors influencing H/L ratios. Finally, the H/L ratio was positively associated with the genetic diversity of offspring. Previous experimental studies have found that individuals with higher genetic diversity show increased levels of circulating glucocorticoids, which in turn are directly responsible for increasing H/L ratios. On this basis, we suggest that a positive effect of genetic diversity on corticosterone levels may explain the observed association between H/L ratios and individual heterozygosity. Overall, this study highlights the utility of leucocyte profiles to study stress in wild bird populations and poses an interesting question about the effects of individual genetic diversity on haematological response to stress. [source] Isolation of microsatellite loci in the pollinating fig wasp of Ficus hispida, Ceratosolen solmsiINSECT SCIENCE, Issue 4 2008Hao Yu Abstract Microsatellite loci were isolated for Ceratosolen solmsi, pollinator of the dioecious Ficus hispida. We developed nine polymorphic microsatellite loci based on the method of polymerase chain reaction isolation of microsatellite arrays (PIMA). Enrichment of genomic libraries was performed by random amplified polymorphic DNA (RAPD). A subset of 38 positive clones was sequenced; 15 clones showed microsatellite loci. We tested 15 designed primer pairs and nine of them produced polymorphic amplification in 48 individual wasps collected from different fruits of the dioecious host fig Ficus hispida in China. Among the 48 individuals, 49 alleles were obtained at the nine loci. The observed heterozygosity ranged between 0.357 and 0.634. [source] Sexual vs. asexual reproduction in an ecosystem engineer: the massive coral Montastraea annularisJOURNAL OF ANIMAL ECOLOGY, Issue 2 2007NICOLA L. FOSTER Summary 1Long-lived sedentary organisms with a massive morphology are often assumed to utilize a storage effect whereby the persistence of a small group of adults can maintain the population when sexual recruitment fails. However, employing storage effects could prove catastrophic if, under changing climatic conditions, the time period between favourable conditions becomes so prolonged that the population cannot be sustained solely be sexual recruitment. When a species has multiple reproductive options, a rapidly changing environment may favour alternative asexual means of propagation. 2Here, we revisit the importance of asexual dispersal in a massive coral subject to severe climate-induced disturbance. Montastraea annularis is a major framework-builder of Caribbean coral reefs but its survival is threatened by the increasing cover of macroalgae that prevents settlement of coral larvae. 3To estimate levels of asexual recruitment within populations of M. annularis, samples from three sites in Honduras were genotyped using four, polymorphic microsatellite loci. 4A total of 114 unique genets were identified with 8% consisting of two or more colonies and an exceptionally large genet at the third site comprising 14 colonies. 5At least 70% of multicolony genets observed were formed by physical breakage, consistent with storm damage. 6Our results reveal that long-lived massive corals can propagate using asexual methods even though sexual strategies predominate. [source] Primers from the orders Osteoglossiform and Siluriform detect polymorphic microsatellite loci in sun-catfish, Horabagrus brachysoma (Teleostei: Bagridae)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2006A. Gopalakrishnan Summary Horabagrus brachysoma (sun-catfish, Bagridae, Siluriformes) is a valuable ornamental and food fish. The stock structure of H. brachysoma, necessary to conserve its declining natural populations, is not known. Twenty-five primers developed for four fish species belonging to the orders Siluriform (3) and Osteoglossiform (1) were tested and eight primers amplified microsatellite loci in H. brachysoma. The results demonstrate that cross-priming between fish species belonging to different families and even to different orders can yield microsatellite loci. Five of eight primers each amplified two loci. However, the loci that had repeat motifs after sequencing were considered only for genotyping. Finally, eight loci were polymorphic with hree to seven alleles. Individual fish genotype data (n = 42; 21 each in two rivers) at each locus was analysed. Significant genetic heterogeneity was detected at six loci. The identified loci exhibited potential for use in population genetics application in H. brachysoma. [source] Microsatellites assessment of Chinese sturgeon (Acipenser sinensis Gray) genetic variabilityJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2005N. Zhao Summary Four microsatellites were used to examine the genetic variability of the spawning stocks of Chinese sturgeon, Acipenser sinensis, from the Yangtze River sampled over a 3-year period (1999,2001). Within 60 individuals, a total of 28 alleles were detected over four polymorphic microsatellite loci. The number of alleles per locus ranged from 4 to 15, with an average allele number of 7. The number of genotypes per locus ranged from 6 to 41. The genetic diversity of four microsatellite loci varied from 0.34 to 0.67, with an average value of 0.54. For the four microsatellite loci, the deviation from the Hardy,Weinberg equilibrium was mainly due to null alleles. The mean number of alleles per locus and the mean heterozygosity were lower than the average values known for anadromous fishes. Fish were clustered according to their microsatellite characteristics using an unsupervised ,Artificial Neural Networks' method entitled ,Self-organizing Map'. The results revealed no significant genetic differentiation considering genetic distance among samples collected during different years. Lack of heterogeneity among different annual groups of spawning stocks was explained by the complex age structure (from 8 to 27 years for males and 12 to 35 years for females) of Chinese sturgeon, leading to formulate an hypothesis about the maintenance of genetic diversity and stability in long-lived animals. [source] Population genetic structure of the round stingray Urobatis halleri (Elasmobranchii: Rajiformes) in southern California and the Gulf of CaliforniaJOURNAL OF FISH BIOLOGY, Issue 2 2010S. M. Plank The round stingray, Urobatis halleri, is a viviparous elasmobranch that inhabits inshore, benthic habitats ranging from the western U.S.A. to Panama. The population genetic structure of this species was inferred with seven polymorphic microsatellite loci in samples collected at three sites in coastal southern California, one near Santa Catalina Island, California and one in the eastern Gulf of California. Urobatis halleri is relatively common, but little is known of its movement patterns or population structure. Small FST values (,0·0017 to 0·0005) suggested little structure among coastal populations of southern and Baja California. The population sampled at Santa Catalina Island, which is separated by a deep-water channel from the coastal sites, however, was significantly divergent (large FST, 0·0251) from the other populations, suggesting low connectivity with coastal populations. The Santa Catalina Island population also had the lowest allele richness and lowest average heterozygosity, suggesting recent population bottlenecks in size. [source] Genetic Diversity of Landraces in Gossypium arboreum L. Race sinense Assessed with Simple Sequence Repeat MarkersJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2006Wang-Zhen Guo Abstract Asiatic cotton (Gossypium arboreum L.) is an "Old World" cultivated cotton species, the sinense race of which is planted extensively in China. This species is still used in the current tetraploid cotton breeding program as an elite germplasm line, and is also used as a model for genomic research in Gossypium. In the present study, 60 cotton microsatellite markers, averaging 4.6 markers for each A-genome chromosome, were chosen to assess the genetic diversity of 109 accessions. These included 106 G. arboreum landraces, collected from 18 provinces throughout four Asiatic cotton-growing regions in China. A total of 128 alleles were detected, with an average of 2.13 alleles per locus. The largest number of alleles, as well as the maximum number of polymorphic loci, was detected in the A03 linkage group. No polymorphic alleles were detected on chromosome 10. The polymorphism information content for the 22 polymorphic microsatellite loci varied from 0.52 to 0.98, with an average of 0.89. Genetic diversity analysis revealed that the landraces in the Southern region had more genetic variability than those from the other two regions, and no significant difference was detected between landraces in the Yangtze and the Yellow River Valley regions. These findings are consistent with the history of sinense introduction, with the Southern region being the presumed center of origin for Chinese Asiatic cotton, and with subsequent northeastward extension to the Yangtze and Yellow River Valleys. Cluster analysis, based on simple sequence repeat data for 60 microsatellite loci, clearly differentiated Vietnamese and G. herbaceum landraces from the sinense landrace. No relationship between inter-variety similarity and geographical ecological region was observed. The present findings indicate that the Southern region landraces may have been directly introduced into the provinces in the middle and lower Yangtze River Valley, where Asiatic cotton was most extensively grown, and further race sinense crops were subsequently produced. (Managing editor: Ya-Qin Han) [source] Genetic variability and differentiation in red deer (Cervus elaphus) from Scotland and EnglandJOURNAL OF ZOOLOGY, Issue 3 2006S. S. Hmwe Abstract Samples from 69 British red deer Cervus elaphus scoticus from seven populations in Scotland and England were analysed with respect to variability within and differentiation among stocks using 11 polymorphic microsatellite loci and 439 bp of the mitochondrial control region. The results clearly showed the effects of anthropogenic factors on British red deer. On the whole, variability values were within the species' reported range. The island population of Islay, Scotland, however, while showing average microsatellite variability, exhibited no mitochondrial variation at all. One microsatellite locus was monomorphic in three Scottish populations (Islay, Dunachton and Achnacarry). Overall and pairwise FST values indicate considerable differentiation among the populations studied, but Dunachton and Achnacarry, two adjacent populations free from recorded introductions, showed only a little differentiation and were paired in trees based on genetic distances. In terms of variability, no statistically significant differences were observed between island and mainland populations and the overall test of isolation by distance was negative. Possible reasons for the genetic patterns observed, such as differences in human impact on the populations, are discussed. [source] POPULATION STRUCTURE IN AN INSHORE CETACEAN REVEALED BY MICROSATELLITE AND mtDNA ANALYSIS: BOTTLENOSE DOLPHINS (TURSIOPS SP.) IN SHARK BAY, WESTERN AUSTRALIAMARINE MAMMAL SCIENCE, Issue 1 2004Michael Krützen Abstract We examined population substructure of bottlenose dolphins (Tursiops sp). in Shark Bay, Western Australia, using 10 highly polymorphic microsatellite loci, and mitochondrial DNA (mtDNA). For microsatellite analysis, 302 different animals were sampled from seven localities throughout the bay. Analysis of genetic differentiation between sampling localities showed a significant correlation between the number of migrants (Nm) calculated from FST, RST and private alleles, and distance between localities,a pattern of isolation-by-distance. For mtDNA, 220 individuals from all seven localities were sequenced for a 351 base pair fragment of the control region, resulting in eight haplotypes, with two distinct clusters of haplotypes. Values of FST and (,)ST for mtDNA yielded statistically significant differences, mostly between localities that were not adjacent to each other, suggesting female gene flow over a scale larger than the sampled localities. We also observed a significant correlation between the number of female migrants calculated from FST and ,ST and the distance of sampling localities. Our results indicate that dispersal in female dolphins in Shark Bay is more restricted than that of males. [source] Linking the planktonic and benthic habitat: genetic structure of the marine diatom Skeletonema marinoiMOLECULAR ECOLOGY, Issue 20 2010ANNA GODHE Abstract Dormant life stages are important strategies for many aquatic organisms. The formation of resting stages will provide a refuge from unfavourable conditions in the water column, and their successive accumulation in the benthos will constitute a genetic reservoir for future planktonic populations. We have determined the genetic structure of a common bloom-forming diatom, Skeletonema marinoi, in the sediment and the plankton during spring, summer and autumn two subsequent years (2007,2009) in Gullmar Fjord on the Swedish west coast. Eight polymorphic microsatellite loci were used to assess the level of genetic differentiation and the respective gene diversity of the two different habitats. We also determined the degree of genetic differentiation between the seed banks inside the fjord and the open sea. The results indicate that Gullmar Fjord has one dominant endogenous population of S. marinoi, which is genetically differentiated from the open sea population. The fjord population is encountered in the plankton and in the sediment. Shifts from the dominant population can happen, and in our study, two genetically differentiated plankton populations, displaying reduced genetic diversity, occurred in September 2007 and 2008. Based on our results, we suggest that sill fjords maintain local long-lived and well-adapted protist populations, which continuously shift between the planktonic and benthic habitats. Intermittently, short-lived and mainly asexually reproducing populations can replace the dominant population in the water column, without influencing the genetic structure of the benthic seed bank. [source] Mitochondrial and microsatellite DNA markers reveal a Balkan origin for the highly invasive horse-chestnut leaf miner Cameraria ohridella (Lepidoptera, Gracillariidae)MOLECULAR ECOLOGY, Issue 16 2009R. VALADE Abstract Biological invasions usually start with a small number of founder individuals. These founders are likely to represent a small fraction of the total genetic diversity found in the source population. Our study set out to trace genetically the geographical origin of the horse-chestnut leafminer, Cameraria ohridella, an invasive microlepidopteran whose area of origin is still unkown. Since its discovery in Macedonia 25 years ago, this insect has experienced an explosive westward range expansion, progressively colonizing all of Central and Western Europe. We used cytochrome oxidase I sequences (DNA barcode fragment) and a set of six polymorphic microsatellites to assess the genetic variability of C. ohridella populations, and to test the hypothesis that C. ohridella derives from the southern Balkans (Albania, Macedonia and Greece). Analysis of mtDNA of 486 individuals from 88 localities allowed us to identify 25 geographically structured haplotypes. In addition, 480 individuals from 16 populations from Europe and the southern Balkans were genotyped for 6 polymorphic microsatellite loci. High haplotype diversity and low measures of nucleotide diversities including a significantly negative Tajima's D indicate that C. ohridella has experienced rapid population expansion during its dispersal across Europe. Both mtDNA and microsatellites show a reduction in genetic diversity of C. ohridella populations sampled from artificial habitats (e.g. planted trees in public parks, gardens, along roads in urban or sub-urban areas) across Europe compared with C. ohridella sampled in natural stands of horse-chestnuts in the southern Balkans. These findings suggest that European populations of C. ohridella may indeed derive from the southern Balkans. [source] Discovery of a large clonal patch of a social amoeba: implications for social evolutionMOLECULAR ECOLOGY, Issue 6 2009OWEN M GILBERT Abstract Studies of genetic population structures of clonally reproducing macro-organisms have revealed large areas where only one clone is found. These areas, referred to as clonal patches, have not been shown to occur in free-living microbes until now. In free-living microbes, high genetic diversity at local scales is usually maintained by high rates of dispersal. We report, however, a highly dense, 12-m clonal patch of the social amoeba Dictyostelium discoideum in a cattle pasture located in a Texas Gulf Coast prairie. We confirm the presence of only one clone by the analysis of 65 samples and amplification of 10 polymorphic microsatellite loci. Samplings of additional cattle pastures nearby showed higher clonal diversity, but with a density of D. discoideum isolates lower than in the clonal patch. These findings show that high rates of microbial dispersal do not always produce genetic diversity at local scales, contrary to the findings of previous studies. The existence of clonal patches may be particularly important for microbial social evolution. [source] Strong population structure despite evidence of recent migration in a selfing hermaphroditic vertebrate, the mangrove killifish (Kryptolebias marmoratus)MOLECULAR ECOLOGY, Issue 13 2007ANDREY TATARENKOV Abstract We employ a battery of 33 polymorphic microsatellite loci to describe geographical population structure of the mangrove killifish (Kryptolebias marmoratus), the only vertebrate species known to have a mixed-mating system of selfing and outcrossing. Significant population genetic structure was detected at spatial scales ranging from tens to hundreds of kilometres in Florida, Belize, and the Bahamas. The wealth of genotypic information, coupled with the highly inbred nature of most killifish lineages due to predominant selfing, also permitted treatments of individual fish as units of analysis. Genetic clustering algorithms, neighbour-joining trees, factorial correspondence, and related methods all earmarked particular killifish specimens as products of recent outcross events that could often be provisionally linked to specific migration events. Although mutation is the ultimate source of genetic diversity in K. marmoratus, our data indicate that interlocality dispersal and outcross-mediated genetic recombination (and probably genetic drift also) play key proximate roles in the local ,clonal' dynamics of this species. [source] Multiple paternity in a natural population of a wild tobacco fly, Bactrocera cacuminata (Diptera: Tephritidae), assessed by microsatellite DNA markersMOLECULAR ECOLOGY, Issue 11 2007SIMON D. SONG Abstract Mating frequency has important implications for patterns of sexual selection and sexual conflict and hence for issues such as speciation and the maintenance of genetic diversity. Knowledge of natural mating patterns can also lead to more effective control of pest tephritid species, in which suppression programmes, such as the sterile insect technique (SIT) are employed. Multiple mating by females may compromise the success of SIT. We investigated the level of polyandry and sperm utilization in a Brisbane field population of the tropical fruit fly, Bactrocera cacuminata (Hering), using seven polymorphic microsatellite loci. The offspring of 22 wild-caught gravid females were genotyped to determine the number of males siring each brood and paternity skew, using the programs gerud and scare. Our data showed that 22.7% of females produced offspring sired by at least two males. The mean number of mates per female was 1.72. Paternal contributions of double-sired broods were skewed with the most successful male having sired between 76.9% and 87.5% of the offspring. These results have implications for SIT, because the level of remating we have identified would indicate that wild females could mate with one or more resident fertile males. [source] Detection and visualization of spatial genetic structure in continuous Eucalyptus globulus forestMOLECULAR ECOLOGY, Issue 4 2007TIM H. JONES Abstract Visualizing the pattern of variation using microsatellites within a Eucalyptus globulus forest on the island of Tasmania provided surprising insights into the complex nature of the fine-scale spatial genetic structure that resides in these forests. We used spatial autocorrelation and principal coordinate analysis to compare fine-scale genetic structure between juvenile and mature cohorts in a study area, 140 m in diameter, located within a typical, continuous E. globulus forest. In total, 115 juvenile and 168 mature individuals were genotyped with eight highly polymorphic microsatellite loci. There was no significant difference in the level of genetic diversity between cohorts. However, there were differences in the spatial distribution of the genetic variation. Autocorrelation analysis provided clear evidence for significant spatial genetic structure in the mature cohort and significant, but weaker, structure in the juvenile cohort. The spatial interpolation of principal coordinate axes, derived from ordination of the genetic distance matrix between individuals, revealed a spatially coherent family group which was evident in both cohorts. Direct comparison of the genetic structure within each cohort allowed visualization of a shift in the spatial distribution of genetic variation within the population of approximately 10 m. As the shift coincided with the direction of prevailing winds, it is hypothesized that this phenomenon is due to downwind dispersal of seeds and is indicative of the important role of prevailing winds in forcing eastward gene flow in these high-latitude forests. [source] Deep genetic subdivision within a continuously distributed and highly vagile marine mammal, the Steller's sea lion (Eumetopias jubatus)MOLECULAR ECOLOGY, Issue 10 2006J. I. HOFFMAN Abstract The Steller's sea lion Eumetopias jubatus is an endangered marine mammal that has experienced dramatic population declines over much of its range during the past five decades. Studies using mitochondrial DNA (mtDNA) have shown that an apparently continuous population includes a strong division, yielding two discrete stocks, western and eastern. Based on a weaker split within the western stock, a third Asian stock has also been defined. While these findings indicate strong female philopatry, a recent study using nuclear microsatellite markers found little evidence of any genetic structure, implying extensive paternal gene flow. However, this result was at odds with mark,recapture data, and both sample sizes and genetic resolution were limited. To address these concerns, we increased analytical power by genotyping over 700 individuals from across the species' range at 13 highly polymorphic microsatellite loci. We found a clear phylogenetic break between populations of the eastern stock and those of the western and Asian stocks. However, our data provide little support for the classification of a separate Asian stock. Our findings show that mtDNA structuring is not due simply to female philopatry, but instead reflects a genuine discontinuity within the range, with implications for both the phylogeography and conservation of this important marine mammal. [source] Fat-tailed gene flow in the dioecious canopy tree species Fraxinus mandshurica var. japonica revealed by microsatellitesMOLECULAR ECOLOGY, Issue 10 2006S. GOTO Abstract Pollen flow, seed dispersal and individual reproductive success can be simultaneously estimated from the genotypes of adults and offspring using stochastic models. Using four polymorphic microsatellite loci, gene flow of the wind-pollinated and wind-seed-dispersed dioecious tree species, Fraxinus mandshurica var. japonica, was quantified in a riparian forest, in northern Japan. In a 10.5-ha plot, 74 female adults, 76 male adults and 292 current-year seedlings were mapped and genotyped, together with 200 seeds. To estimate dispersal kernels of pollen and seeds, we applied normal, exponential power, Weibull, bivariate t -distribution kernels, and two-component models consisting of two normal distribution functions, one with a small and one with a large variance. A two-component pollen flow model with a small contribution (26.1%) from short-distance dispersal (, = 7.2 m), and the rest from long-distance flow (, = 209.9 m), was chosen for the best-fitting model. The average distance that integrated pollen flows inside and outside the study plot was estimated to be 196.8 m. Tree size and flowering intensity affected reproduction, and there appeared to be critical values that distinguished reproductively successful and unsuccessful adults. In contrast, the gene flow model that estimated both pollen and seed dispersal from established seedlings resulted in extensive seed dispersal, and the expected spatial genetic structures did not satisfactorily fit with the observations, even for the selected model. Our results advanced small-scale individual-based parentage analysis for quantifying fat-tailed gene flow in wind-mediated species, but also clarified its limitations and suggested future possibilities for gene flow studies. [source] Microsatellites reveal a lack of structure in Australian populations of the diamondback moth, Plutella xylostella (L.)MOLECULAR ECOLOGY, Issue 1 2006N. M. ENDERSBY Abstract The diamondback moth, Plutella xylostella, is renowned for developing resistance to insecticides and causing significant economic damage to Brassica vegetable crops throughout the world. Yet despite its economic importance, little is known about the population structure and movement patterns of this pest both at local and regional scales. In Australia, the movement patterns and insecticide resistance status of P. xylostella infesting canola, vegetables, forage brassicas and weeds have fundamental implications for the management of this pest. Here we use six polymorphic microsatellite loci to investigate population structure and gene flow in Australian populations of P. xylostella. Samples of P. xylostella from New Zealand, Malaysia, Indonesia and Kenya were also scored at these loci. We found no evidence of population structure within Australia, with most populations having low inbreeding coefficients and in Hardy,Weinberg equilibrium. In addition, a sample from the North Island of New Zealand was indistinguishable from the Australian samples. However, large genetic differences were found between the Australia/New Zealand samples and samples from Kenya, Malaysia and Indonesia. There was no relationship between genetic distance and geographic distance among Australian and New Zealand samples. Two of the loci were found to have null alleles, the frequency of which was increased in the populations outside the Australia/New Zealand region. We discuss these results with reference to insecticide resistance management strategies for P. xylostella in Australia. [source] | |||||||||||||