Isolation (with enrichment) and characterization of trinucleotide microsatellites from Phlebotomus perniciosus,a vector of Leishmania infantum

Mitochondrial DNA characterization of the sandfly Phlebotomus perniciosus has not resolved the population structure of its Iberian lineage. For this purpose, four AGC‐ and seven AGG‐class microsatellite loci were characterized, after their isolation using Biotin‐Avidin enrichment and the screening of plasmid libraries by polymerase chain reaction. Of the five polymorphic loci analysed in four Spanish populations, four showed patterns of allele diversity consistent with migration from a southern Ice Age refuge. Estimates of the historical migration rates of P. perniciosus will help to predict the effects of global warming on its range and that of Leishmania infantum, the parasitic protozoan it transmits.     

Post-ice age recolonization and differentiation of Fucus serratus L. (Phaeophyceae; Fucaceae) populations in Northern Europe

The seaweed Fucus serratus is hypothesized to have evolved in the North Atlantic and present populations are thought to reflect recolonization from a southern refugium since the last glacial maximum 18 000-20 000 years bp. We examined genetic structure across several spatial scales by analysing seven microsatellite loci in populations collected from 21 localities throughout the species' range. Spatial auto-correlation analysis of seven microsatellite loci revealed no evidence for spatial clustering of alleles on a scale of 100 m despite limited gamete dispersal in F. serratus of approximately 2 m from parental individuals. Pairwise theta analysis suggested that the minimal panmictic unit for F. serratus was between 0.5 and 2 km. Isolation by distance was significant along some contiguous coastlines. Population differentiation was strong within the Skagerrak-Kattegat-Baltic Seas (SKB) (global theta= 0.17) despite a short history of approximately 7500 years. A neighbour-joining tree based on Reynold's distances computed from the microsatellite data revealed a central assemblage of populations on the Brittany Peninsula surrounded by four well-supported clusters consisting of the SKB, the North Sea (Ireland, Helgoland), and two populations from the northern Spanish coast. Samples from Iceland and Nova Scotia were most closely aligned with northwest Sweden and Brittany, respectively. When sample sizes were standardized (N = 41), allelic diversity was twofold higher for Brittany populations than for populations to the north and threefold higher than southern populations. The Brittany region may be a refugium or a recolonized area, whereas the Spanish populations most likely reflect present-day edge populations that have undergone repeated bottlenecks as a consequence of thermally induced cycles of recolonization and extinction.     

Genetic Diversity and Population Structure for the Conservation of Giant Spiny Frog(Quasipaa spinosa) Using Microsatellite Loci and Mitochondrial DNA

The giant spiny frog(Quasipaa spinosa) is an endangered species with a relatively small distribution limited to southern China and Northern Vietnam. This species is becoming increasingly threatened because of over-exploitation and habitat degradation. This study provides data on the genetic diversity and population genetic structure of the giant spiny frog to facilitate the further development of effective conservation recommendations for this economically important but threatened species. We examined 10 species-specific microsatellite loci and Cyt b genes(562 bp) collected from 13 wild populations across the entire range of this species. Results of 10 microsatellite loci analysis showed a generally high level of genetic diversity. Moreover, the genetic differentiation among all 12 populations was moderate to large(overall F_(ST) = 0.1057). A total of 51 haplotypes were identified for Cyt b, which suggests high haplotype nucleotide diversities. Phylogeographic and population structure analyses using both DNA markers suggested that the wild giant spiny frog can be divided into four distinct major clades, i.e., Northern Vietnam, Western China, Central China, and Eastern China. The clades with significant genetic divergence are reproductively isolated, as evidenced by a high number of private alleles and strong incidence of failed amplification in microsatellite loci. Our research, coupled with other studies, suggests that Q. spinosa might be a species complex within which no detectable morphological variation has been revealed. The four phylogenetic clades and some subclades with distinct geographical distribution should be regarded as independent management units for conservation purposes.     

Sandflies of the Phlebotomus perniciosus complex: mitochondrial introgression and a new sibling species of P. longicuspis in the Moroccan Rif

The bloodsucking adult females of Phlebotomus perniciosus Newstead and P. longicuspis Nitzulescu (Diptera: Psychodidae) are important vectors of the protozoan Leishmania infantum Nicolle (Kinetoplastida: Trypanosomatidae) in western Mediterranean countries. The species status of the two phlebotomine sandflies was assessed, along with the epidemiological implications. Individual sandflies from three Moroccan Rif populations were characterized morphologically, isoenzymatically (by the isoelectrofocusing of alleles at the polymorphic enzyme loci of HK, GPI and PGM), and by comparative DNA sequence analysis of a fragment of mitochondrial Cytochrome b (mtDNA). By reference to the character profiles of specimens from other locations, including southern Spain and the type-locality countries, the Moroccan flies were placed in three lineages: first, the lineage of P. perniciosus, which contained two mtDNA sublineages, one (pnt) widely distributed and associated with the morphology of the male types from Malta, and the other (pna) associated with a P. longicuspis-like male morphology; second, the lineage of P. longicuspis sensu stricto, including typical forms from Tunisia; and third, a new sibling species of P. longicuspis. The mtDNA sublineage (pnt) of typical P. perniciosus was also found in some P. longicuspis from Morocco, indicating interspecific hybridization. The typical race of P. perniciosus occurs in Italy as well as in Malta, Tunisia and Morocco. It is replaced in southern Spain by the Iberian race (with the pni mtDNA sublineage). The discovery of interspecific gene introgression and a new sibling species mean that previous records of the two morphospecies do not necessarily reflect their true vectorial roles or geographical and ecological distributions.     

Genetic structure in northeastern populations of the Alpine newt (Triturus alpestris): evidence for post-Pleistocene differentiation

Genetic variation in 13 populations of the Alpine newt, Triturus alpestris, was assessed at the northeastern margin of its range (southern Poland). Variation at six microsatellite loci was scored in 354 newts, and two mitochondrial DNA fragments (c. 2000 bp) were sequenced in a subset of 27 individuals. Significant differences in allele frequencies and the presence of private alleles determined genetic units corresponding to three separate mountain ranges, i.e. the Carpathian, Sudetes and Holy Cross Mountains. F(ST)'s were three times greater in among than in within mountain range pairwise comparisons. An assignment test and pairwise F(ST)'s suggested relatively high levels of gene flow at the local level, although the Sudetes populations revealed some subtle structuring. Genetic variation was lower in the Carpathians and Holy Cross Mountains. The geographic pattern of mitochondrial DNA variation indicated that these newt populations originated from a single glacial refugium/founder population, and that the colonization of southern Poland took place in an easterly direction. The data show that substantial neutral variation and between group divergence has accumulated relatively quickly in these low-vagility organisms. The Alpine newt case exemplifies species history as a factor determining patterns of genetic diversity in marginal populations.     

Population structure of the African savannah elephant inferred from mitochondrial control region sequences and nuclear microsatellite loci

Two hundred and thirty-six mitochondrial DNA nucleotide sequences were used in combination with polymorphism at four nuclear microsatellite loci to assess the amount and distribution of genetic variation within and between African savannah elephants. They were sampled from 11 localities in eastern, western and southern Africa. In the total sample, 43 haplotypes were identified and an overall nucleotide diversity of 2.0% was observed. High levels of polymorphism were also observed at the microsatellite loci both at the level of number of alleles and gene diversity. Nine to 14 alleles per locus across populations and 44 alleles in the total sample were found. The gene diversity ranged from 0.51 to 0.72 in the localities studied. An analysis of molecular variance showed significant genetic differentiation between populations within regions and also between regions. The extent of subdivision between populations at the mtDNA control region was approximately twice as high as shown by the microsatellite loci (mtDNA F(ST) = 0.59; microsatellite R(ST) = 0.31). We discuss our results in the light of Pleistocene refugia and attribute the observed pattern to population divergence in allopatry accompanied by a recent population admixture following a recent population expansion.     

Phylogeography of isolated freshwater three-spined stickleback Gasterosteus aculeatus populations in the Adriatic Sea basin

Analyses of mitochondrial (mt) DNA and microsatellite variation were carried out to examine the relationships between 10 freshwater populations of three-spined sticklebacks Gasterosteus aculeatus along the eastern coast of the Adriatic Sea. Partial sequences of the mtDNA control region and cytochrome b gene, in addition to 15 microsatellite loci, were used to analyse populations from four isolated river catchments. Results uncovered an Adriatic lineage that was clearly divergent from the European lineage, and confirmed that the most divergent and ancient populations are located within the Adriatic lineage as compared with other European populations. Two northern Adriatic populations formed independent clades within the European mitochondrial lineage, suggesting different colonization histories of the different Adriatic populations. Nuclear marker analyses also indicated deep divergence between Adriatic and European populations, albeit with some discordance between the mtDNA phylogeny of the northern Adriatic populations, further highlighting the strong differentiation among the Adriatic populations. The southern populations within the Adriatic lineage were further organized into distinct clades corresponding to respective river catchments and sub-clades corresponding to river tributaries, reflecting a high degree of population structuring within a small geographic region, concurrent with suggestions of existence of several microrefugia within the Balkan Peninsula. The highly divergent clades and haplotypes unique to the southern Adriatic populations further suggest, in accordance with an earlier, more limited survey, that southern Adriatic populations represent an important reservoir for ancient genetic diversity of G. aculeatus.     

Genetic differentiation of pink salmon oncorhynchus gorbuscha Walbaum in the Asian part of the range

Genetic variation at 19 allozyme (including 11 polymorphic) and 10 microsatellite loci was examined in the population samples of odd- and even-broodline pink salmon from the southern part of Sakhalin Island, Southern Kuril Islands, and the northern coast of the Sea of Okhotsk. The estimates of relative interpopulation component of genetic variation over the allozyme loci, per broodline, were on average 0.43% (GST), while over the microsatellite loci it was 0.26% (the theta(ST) coefficient, F-statistics based on the allele frequency variance), and 0.90% (the rho(ST) coefficient, R-statistics based on the allele size variance). The values of interlinear component constituted 2.34, 0.31, and 1.05% of the total variation, respectively. Using the allozyme loci, statistically significant intralinear heterogeneity was demonstrated among the regions, as well as among the populations of Southern Sakhalin Island. Multivariate scaling based on the allozyme data demonstrated regional clustering of the sample groups, representing certain populations during the spawning run or in different years. Most of the microsatellite loci examined were found to be highly polymorphic (mean heterozygosity > 0.880). The estimates of interlinear, interregional, and interpopulation variation over these loci in terms of theta(ST) values were substantially lower than in terms of rho(ST) values. Regional genetic differentiation, mostly expressed at the allozyme loci among the populations from the northern and southern parts of the Sea of Okhotsk (i.e., between the Sakhalin and Kuril populations), was less expressed at the microsatellite loci. The differentiation between these regions observed can be considered as the evidence in favor of a large-scale isolation by distance characterizing Asian pink salmon. It is suggested that in pink salmon, low genetic differentiation at neutral microsatellite loci can be explained by extremely high heterozygosity,of the loci themselves, as well as by the migration gene exchange among the populations (the estimate of the genetic migration coefficient inferred from the "private" allele data constituted 2.6 to 3.4%), specifically, by the ancient migration exchange, which occurred during postglacial colonization and colonization of the range.     

Population structure within and between subspecies of the Mediterranean triplefin fish Tripterygion delaisi revealed by highly polymorphic microsatellite loci

Although F(ST) values are widely used to elucidate population relationships, in some cases, when employing highly polymorphic loci, they should be regarded with caution, particularly when subspecies are under consideration. Tripterygion delaisi presents two subspecies that were investigated here, using 10 microsatellite loci. A Bayesian approach allowed us to clearly identify both subspecies as two different evolutionary significant units. However, low F(ST) values were found between subspecies as a consequence of the large number of alleles per locus, while homoplasy could be disregarded as indicated by the standardized genetic distance G'(ST). Heterozygosity saturation was observed in highly polymorphic loci containing more than 15 alleles, and this threshold was used to define two loci pools. The less variable loci pool revealed higher genetic variance between subspecies, while the more variable pool showed higher genetic variance between populations. Furthermore, higher differentiation was also observed between populations using G'(ST) with the more variable loci. Nonetheless, a more reliable population structure within subspecies was obtained when all loci were included in the analyses. In T. d. xanthosoma, isolation by distance was detected between the eight analysed populations, and six genetically homogeneous clusters were inferred by Bayesian analyses that are in accordance with F(ST) values. The neighbourhood-size method also indicated rather small dispersal capabilities. In conclusion, in fish with limited adult and larval dispersal capabilities, continuous rocky habitat seems to allow contact between populations and prevent genetic differentiation, while large discontinuities of sand or deep-water channels seems to reduce gene flow.     

Source populations of Quercus glauca in the last glacial age in Taiwan revealed by nuclear microsatellite markers

In this work, we attempted to study genetic differentiation between populations of Quercus glauca in Taiwan using nuclear microsatellite markers to infer the potential refugium in the last glaciation stage. Four microsatellite loci for 20 individuals each in 10 populations of Taiwan were analyzed. We found that Q. glauca has relatively high within-population diversity (H(E) = 0.741) and low population differentiation (F(ST) = 0.042) but shows isolation by distance. The most divergent populations, according to the average F(ST) for individual populations in comparison with every other population, were found in populations Cy, Sa, and Hy in southern Taiwan and Pa in north-central Taiwan. Moreover, populations Cy, Sa, and Pa were recognized as being the source populations for gene recolonization after the last glaciation stage. In addition, the three sites of Wu, Ym, and Cy exhibited the highest gene diversities that coincided with populations with the highest chloroplast DNA variations. This may have resulted from an admixture of colonization routes. In conclusion, observations of the most divergent populations and source populations suggest that southern and probably north-central Taiwan may have potentially been refugia for Q. glauca in the last glaciation. This agrees with the possible refugium in southern Taiwan revealed by a previous study using chloroplast DNA markers.     

Genetic structure in the coral-reef-associated Banggai cardinalfish, Pterapogon kauderni

In this study, we used 11 polymorphic microsatellite loci to show that oceanic distances as small as 2-5 km are sufficient to produce high levels of population genetic structure (multilocus F(ST) as high as 0.22) in the Banggai cardinalfish (Pterapogon kauderni), a heavily exploited reef fish lacking a pelagic larval dispersal phase. Global F(ST) among all populations, separated by a maximum distance of 203 km, was 0.18 (R(ST) = 0.35). Moreover, two lines of evidence suggest that estimates of F(ST) may actually underestimate the true level of genetic structure. First, within-locus F(ST) values were consistently close to the theoretical maximum set by the average within-population heterozygosity. Second, the allele size permutation test showed that R(ST) values were significantly larger than F(ST) values, indicating that populations have been isolated long enough for mutation to have played a role in generating allelic variation among populations. The high level of microspatial structure observed in this marine fish indicates that life history traits such as lack of pelagic larval phase and a good homing ability do indeed play a role in shaping population genetic structure in the marine realm.     

Genetic polymorphism in sympatric species of the genus Phlebotomus, with special reference to Phlebotomus perniciosus and Phlebotomus longicuspis (Diptera, Phlebotomidae)

The Random Amplified Polymorphic DNA assay was used to study genetic variation within and between five Phlebotomus species belonging to three subgenera: P. (Larroussius) ariasi, P. (L.) longicuspis, P. (L.) perniciosus, P.(Paraphlebotomus) sergenti and P. (Phlebotomus) papatasi sympatric in southern Spain and proven vector of leishmaniasis. Two cluster analysis were proposed: one according to sandfly species and populations, the second according individual specimens of Phlebotomus perniciosus, Phlebotomus longicuspis s.l. and intermediate morphological specimens between these species. The results obtained are closely correlated with the taxonomy classically accepted for the subgenera and with the automatic classifications made by other authors which use morphological and isoenzymatic data. The validity of the species Phlebotomus longicuspis is also discussed.     

Allelic frequencies and statistical data obtained from 12 codis STR loci in an admixed population of the Brazilian Amazon

The allelic frequencies of 12 short tandem repeat loci were obtained from a sample of 307 unrelated individuals living in Macapá, a city in the northern Amazon region, Brazil. These loci are the most commonly used in forensics and paternity testing. Based on the allele frequency obtained for the population of Macapá, we estimated an interethnic admixture for the three parental groups (European, Native American and African) of, respectively, 46%, 35% and 19%. Comparing these allele frequencies with those of other Brazilian populations and of the Iberian Peninsula population, no significant distances were observed. The interpopulation genetic distances (F(ST) coefficients) to the present database ranged from F(ST) = 0.0016 between Macapá and Belém to F(ST) = 0.0036 between Macapá and the Iberian Peninsula.     

Microsatellite genetic variation in small and isolated populations of Magnolia sieboldii ssp. japonica

Magnolia sieboldii ssp. japonica, distributed mainly in western Japan, is restricted to high elevation areas (1000-2000 m above sea level) and usually forms small isolated populations. Four microsatellite loci were assayed for 19 populations from six regions spanning the range of distribution, and the levels and distribution of genetic variation were estimated. All four loci were variable, with a total of 39 alleles, but the overall level of microsatellite genetic variation was low, especially compared with a related species, M. obovata. Genetic structure in M. sieboldii was characterised by low intrapopulational genetic variation (A = 3.74 and H(o) = 0.366 on average) and high genetic differentiation even among regional populations. Highly significant isolation-by-distance (IBD) models at the short distance were detected. Genetic drift and limited gene flow was considered to be important in determining the genetic structure within regions. Total genetic differentiation was remarkably high (F(ST) = 0.488 and R(ST) = 0.538), suggesting genetic barriers among regions. Neighbour-joining dendrograms relating the 19 populations, and further analysis on the IBD models, revealed that a stepwise mutation model was more suited than an infinite allele model to explain the genetic differentiation among regions. It is suggested that mutation at microsatellite loci might be influential in generating the genetic differentiation among regions. These results showed the potential of hypervariable microsatellite loci to evaluate the effects of genetic drift and population isolation within regions, and to detect genetic distinctiveness, in spite of the loss of overall genetic variation in M. sieboldii.     

Fine-scale phylogeographical analysis of Mediterranean Anacamptis palustris (Orchidaceae) populations based on chloroplast minisatellite and microsatellite variation

The phylogeographical history of the rare marsh orchid Anacamptis palustris (Orchidaceae) was reconstructed using highly polymorphic chloroplast minisatellite and microsatellite loci. Allelic variation at chloroplast microsatellite loci was due to length variation in poly(A/T) repeats and was informative on a regional scale, but was not sufficient to unravel relationships among populations on a local geographical scale. The minisatellite locus, however, was found to be highly variable. Nine distinct repeat types were found and variation in repeat number occurred in five repeat types. The distribution of chloroplast haplotypes, combining microsatellite and minisatellite repeat type variation, provided a clear phylogeographical picture on a large geographical scale, whereas length variation in one highly polymorphic minisatellite repeat type provided fine-scale phylogeographical information. Mediterranean populations could be divided into four main lineages, a western European lineage, a northern and central Italian lineage, a well-isolated southern Italian (Apulian) lineage, and an eastern European lineage. Variation at the most variable minisatellite repeat type N revealed 19 alleles and allowed the study of seed-mediated gene flow and an estimation of the ratio of pollen to seed flow among neighbouring populations.     

Candidate loci reveal genetic differentiation between temporally divergent migratory runs of Chinook salmon (Oncorhynchus tshawytscha)

Local adaptation is a dynamic process driven by selection that can vary both in space and time. One important temporal adaptation for migratory animals is the time at which individuals return to breeding sites. Chinook salmon (Oncorhynchus tshawytscha) are excellent subjects for studying the genetic basis of temporal adaptation because their high seasonal homing fidelity promotes reproductive isolation leading to the formation of local populations across diverse environments. We tested for adaptive genetic differentiation between seasonal runs of Chinook salmon using two candidate loci; the circadian rhythm gene, OtsClock1b, and Ots515NWFSC, a microsatellite locus showing sequence identity to three salmonid genes central to reproductive development. We found significant evidence for two genetically distinct migratory runs in the Feather River, California (OtsClock1b: F(ST)=0.042, P=0.02; Ots515NWFSC: F(ST)=0.058, P=0.003). In contrast, the fall and threatened spring runs are genetically homogenous based on neutral microsatellite data (F(ST)=-0.0002). Similarly, two temporally divergent migratory runs of Chinook salmon from New Zealand are genetically differentiated based on polymorphisms in the candidate loci (OtsClock1b: F(ST)=0.083, P-value=0.001; Ots515NWFSC: F(ST)=0.095, P-value=0.000). We used an individual-based assignment method to confirm that these recently diverged populations originated from a single source in California. Tests for selective neutrality indicate that OtsClock1b and Ots515NWFSC exhibit substantial departures from neutral expectations in both systems. The large F(ST )estimates could therefore be the result of directional selection. Evidence presented here suggests that OtsClock1b and Ots515NWFSC may influence migration and spawning timing of Chinook salmon in these river systems.     

Geographical variation in the yellow‐legged gull: introgression or convergence from the herring gull?

Yellow-legged gulls Larus michahellis from the Atlantic Iberian coast exhibit some phenotypic similarities with the herring gull L. argentatus from Western Europe. To assess this phenomenon and its possible origin, we compared Mediterranean yellow-legged gulls, Atlantic Iberian yellow-legged gulls and herring gulls for several phenotypic traits (morphology, plumage), and used genetic data to determine the evolutionary history of the Atlantic Iberian yellow-legged gulls. Data from mitochondrial cytochrome b gene and microsatellite loci clearly indicate that Atlantic Iberian gulls are closely related to Mediterranean yellow-legged gulls, and do not show stronger signs of introgression with herring gulls relative to other populations of yellow-legged gulls. Atlantic Iberian yellow-legged gulls are more similar to herring gulls in body size and shape than to other yellow-legged gulls populations, but not in mantle colour and wing-tip pattern. Body size and other phenotypic and life history similarities with the herring gull ( L. argentatus argenteus ) such as voice, winter plumage and breeding phenology, previously described in several studies, might thus be interpreted as convergent characters. Within the yellow-legged gull, the high F _st-values obtained from four nuclear microsatellite loci indicate substantial population structure and reduced levels of gene flow between gull populations in Mediterranean France and Atlantic Iberia. Differences among these populations in breeding phenology and migration patterns, likely resulting from different local selection pressures, might contribute to this low level of gene flow.     

The Atlantic-Mediterranean watershed, river basins and glacial history shape the genetic structure of Iberian poplars

Recent phylogeographic studies have elucidated the effects of Pleistocene glaciations and of Pre-Pleistocene events on populations from glacial refuge areas. This study investigates those effects in riparian trees (Populus spp.), whose particular features may convey enhanced resistance to climate fluctuations. We analysed the phylogeographic structure of 44 white (Populus alba), 13 black (Populus nigra) and two grey (Populus x canescens) poplar populations in the Iberian Peninsula using plastid DNA microsatellites and sequences. We also assessed fine-scale spatial genetic structure and the extent of clonality in four white and one grey poplar populations using nuclear microsatellites and we determined quantitative genetic differentiation (Q(ST) ) for growth traits in white poplar. Black poplar displayed higher regional diversity and lower differentiation than white poplar, reflecting its higher cold-tolerance. The dependence of white poplar on phreatic water was evidenced by strong differentiation between the Atlantic and Mediterranean drainage basins and among river basins, and by weaker isolation by distance within than among river basins. Our results suggest confinement to the lower river courses during glacial periods and moderate interglacial gene exchange along coastlines. In northern Iberian river basins, white poplar had lower diversity, fewer private haplotypes and larger clonal assemblies than in southern basins, indicating a stronger effect of glaciations in the north. Despite strong genetic structure and frequent asexual propagation in white poplar, some growth traits displayed adaptive divergence between drainage and river basins (Q(ST) >F(ST)), highlighting the remarkable capacity of riparian tree populations to adapt to regional environmental conditions.     

Genetic variation of Avicennia marina (Forsk.) Vierh. (Avicenniaceae) in Vietnam revealed by microsatellite and AFLP markers

Genetic variation of Avicennia marina in the costal area of Vietnam was examined using microsatellite and AFLP markers. By using five microsatellite loci a total of 21 alleles were detected. The average number of alleles per locus per population ranged from 1.667 to 3.000. The observed heterozygosity varied from 0.180 to 0.263, with an average of 0.210 indicating relatively low level of genetic variation comparing to the previous studies on A. marina in the worldwide range. The expected heterozygosity was larger than the observed heterozygosity leading to positive inbreeding coefficients in all the six populations. Highly significant departures from Hardy-Weinberg Equilibrium were detected in four populations. AFLP analysis revealed a total of 386 loci, of which 232 (60.1%) were polymorphic. In congruent with microsatellite markers relatively low levels of genetic variation were detected at both gene and nucleotide levels (H = 0.086; pi = 0.0054). Reduced level of genetic variation was found in the central population, and in the southern populations. Both microsatellite and AFLP markers revealed large genetic differentiation (F(ST) = 0.262 and 0.338, respectively) indicating strong genetic structure among regional populations. Pairwise genetic distance by AFLP showed two populations in the north and the other two in the south are closely related each other.     

Microgeographical breeding structure of the tsetse fly, Glossina pallidipes in south-western Kenya

The origins of extant Glossina pallidipes Austen (Diptera: Glossinidae) populations in the ecologically well-studied Lambwe and Nguruman valleys in Kenya are controversial because populations have recovered after seemingly effective attempts to achieve high levels of control. The microgeographical breeding structure of the tsetse fly, G. pallidipes, was investigated by analysing spatial and temporal variation at eight microsatellite loci to test hypotheses about endemism and immigration. Samples were obtained at seasonal intervals from trap sites separated by 200 m to 14 km and arranged into blocks. G. pallidipes populations nearest to Lambwe and Nguruman also were sampled. Spatial analysis indicated that genetic differentiation by genetic drift was much less among trapping sites within Lambwe and Nguruman (F(ST) < or = 0.049) than between them (F(ST) = 0.232). F(ST) between Serengeti and Nguruman was 0.16 and F(ST) between Kodera Forest and Lambwe was 0.15. The genetic variance in G. pallidipes explained by dry and wet seasons (0.33%) was about one-fifth the variance among collection dates (1.6%), thereby indicating reasonable temporal stability of genetic variation. Gene frequencies in Kodera and Serengeti differed greatly from Lambwe and Nguruman, thereby falsifying the hypothesis that Lambwe and Nguruman were repopulated by immigrants. Harmonic mean effective (= breeding) population sizes were 180 in Lambwe and 551 in Nguruman. The genetic data suggest that G. pallidipes in Lambwe and Nguruman have been endemic for long intervals.