Nei's Distance Research Articles

Genetic diversity and population structure of Butea monosperma (Lam.) Taub.- a potential medicinal legume tree

Three molecular marker systems, Random Amplified Polymorphic DNA (RAPD), Inter-Simple Sequence Repeats (ISSR) and Sequence-Related Amplified Polymorphism (SRAP) were employed to investigate the genetic structure and diversity among the 14 natural populations of Butea monosperma collected from different geographical regions of India. Detected by 17 RAPD, 15 ISSR and 11 SRAP primer combinations, the proportions of polymorphic bands were 84.2%, 77.2% and 91.9%, respectively, and the mean Nei's genetic distances among the populations were 0.13, 0.10 and 0.13, respectively. Partitioning of genetic variability by Analysis of molecular variance (AMOVA) revealed that the high genetic diversity was distributed within the populations. AMOVA also revealed that the coefficient of gene differentiation among populations based on FST was very high irrespective of markers used. The overall gene flow among populations (Nm) was very low. Cophenetic correlation coefficients of Nei's distance values and clustering pattern by Mental test were statistically significant for all three marker systems used but poor fit for ISSR data than for RAPD, SRAP and combined data set of all three markers. For all markers, a high similarity in dendrogram topologies was obtained, although some differences were observed with ISSR. The dendrogram obtained by RAPD, SRAP and combined data set of all three markers reflect relationship of most of the populations according to their geographic distribution.

Surnames in Albania: A Study of the Population of Albania through Isonymy

In order to describe the isonymic structure of Albania, the distribution of 3,068,447 surnames was studied in the 12 prefectures and their administrative subdivisions: the 36 districts and 321 communes. The number of different surnames found was 37,184. Effective surname number for the entire country was 1327, the average for prefectures was 653.3 ± 84.3, for districts 365.9 ± 42.0 and for communes 122.6 ± 8.7. These values display a variation of inbreeding between administrative levels in the Albanian population, which can be attributed to the previously published "Prefecture effect". Matrices of isonymic distances between units within administrative levels were tested for correlation with geographic distances. The correlations were highest for prefectures (r= 0.71 ± 0.06 for Euclidean distance) and lowest for communes (r= 0.37 ± 0.011 for Nei's distance). The multivariate analyses (Principal component analysis and Multidimensional Scaling) of prefectures identify three main clusters, one toward the North, the second in Central Albania, and the third in the South. This pattern is consistent with important subclusters from districts and communes, which point out that the country may have been colonised by diffusion of groups in the North-South direction, and from Macedonia in the East, over a pre-existing Illiryan population.

Морфологический и генетический (AFLP) анализы видов тюльпанов родстваTulipa biebersteiniana(Liliaceae)

In populations of four species of tulips, (Tulipa biebersteiniana, T. patens, T. scytica and T. riparia) from the Volgograd, Kurgansk, Orenburg, and Chelyabinsk regions and the Republic of Bashkortostan, genetic diversity was studied by means of morphological and AFLP analysis. A morphological analysis of seven quantitative and two qualitative criteria was carried out. Three selective EcoRI/MseI primer pairs allowed one to genotype 81 individuals from 13 tulip populations with 87 loci. The low level of variability by AFLP loci were revealed in all species, including T. biebersteiniana (P = 20.41%, UH(e) = 0.075), T. patens (26.97%, 0.082), T. scytica (27.53%, 0.086), and T. riparia (27.72%, 0.096). According to the AMOVA results, the variability proportion that characterizes the differences between the four Tulip species was lower (F(CT) = 0.235) than between populations within species (F(ST) = 0.439). Tulipa patens is well differentiated by means of Nei's distances, coordination, and analysis in the STRUCTURE program. An analysis in the STRUCTURE revealed four genetic groups of tulips that are not completely in accordance with the analyzed species. This acknowledges the presence of complicated genetic process in the tulip population.

AFLP analysis of the genetic diversity of closely related rhododendron species of the section rhodorastra (Ericaceae) from Siberia and the Far East of Russia

Using AFLP analysis, the genetic variation in four population samples of Rhododendron ledebourii, three such samples of Rh. dauricum, two samples of Rh. sichotence, and one sample of Rh. mucronulatum was examined. Application of three selective primer pairs provided genotyping of 87 accessions from the four species at 213 loci. An analysis of molecular variance revealed a high level of differences between all four species (F(ST) = 0.172). Populations within the species were also differentiated: for Rh. dauricum F(ST) = 0.245; Rh. ledebourii F(ST) = 0.264; Rh. sichotence F(ST) = 0.034. The highest Nei distance was observed for Rh. mucronulatum with Rh. dauricum and Rh. ledebourii (D = 0.057 and 0.069, respectively). Similarity was observed between the species pairs of Rh. ledebourii-Rh. dauricum (0.032) and Rh. sichotense-Rh. mucronulatum (0.034). The Far Eastern species Rh. sichotense and Rh. mucronulatum were characterized by an elevated level of intrapopulation variation. The data from the AFLP-based analysis of differentiation and variation that were thus obtained were compared with the literature data on the morphological criteria that differentiate the species of interest and those regarding the history of the formation of their ranges. The independence of all the species we examined was confirmed.

Refractive Error and Visual Function Difficulty in a Latino Population

To assess the association of correction of myopia, hyperopia, and astigmatism with self-reported near and distance visual function. Population based, cross-sectional study. A random sample of 4272 Latinos older than 40 years of age from Arizona with both ophthalmic examination and questionnaire data, including answers to the National Eye Institute 25-item Visual Function Questionnaire (NEI VFQ-25). Cases of refractive error (RE) were defined as subjects who met at least 1 of the following criteria in both eyes: myopia, sphere -0.5 diopters (D) or less; hyperopia, sphere 1.0 D or more; or astigmatism, cylinder 0.75 D or more. Uncorrected refractive error (URE) was defined as having RE and achieving 2 lines or more of improvement in visual acuity in both eyes after refraction. The association between RE category and near and distance vision difficulty (as measured by the NEI VFQ-25 near and distance vision subscores) was modeled with ordinal logistic regression, adjusting for age, gender, diabetes, hypertension, income, education, and acculturation. Association between RE correction and near and distance vision difficulty by type of RE (myopia, hyperopia, and astigmatism). Of 4272 participants, 54% had RE. Forty-eight percent of these had myopia, 41% had hyperopia, and 11% had astigmatism. Fourteen percent of myopes, 21% of hyperopes, and 22% of astigmatics had URE. Subjects with myopia, astigmatism, and hyperopia were significantly more likely to report more distance vision difficulty than subjects without RE, regardless of whether they had correction (odds ratios [ORs], 1.7-3.7; P<0.005 for all). Subjects with corrected myopia reported less near vision difficulty than subjects without RE (OR, 0.8; 95% confidence interval [CI], 0.7-0.9). Subjects with uncorrected hyperopia and uncorrected astigmatism reported more near vision difficulty than those without RE (OR, 1.6; 95% CI, 1.2-2.2; and OR, 1.7; 95% CI, 1.0-3.0, respectively). Self-reported distance and near visual function scores were sensitive to nonvision variables, namely, age, gender, diabetes, high blood pressure, acculturation score, income, and education. In this population, correction of any type of RE is not entirely sufficient to restore distance visual function to the level of those without RE. More research is necessary to determine the reasons for this shortcoming.

A study of surnames in china through isonymy

The isonymy structure of 1.28 billion people registered in China's National Citizen Identity Information System was studied at the provincial, prefectural, and county administrative division levels. The isonymy was 0.026 for China as a whole. The average value of isonymy was 0.033 for the 30 provinces, 0.035 for the 334 prefectures, and 0.040 for the 2811 counties. The isonymy in China was much higher than in other countries. This finding may be partly explained by the low number of surnames in the Chinese language. Two regional features can be identified from the geographic distributions of isonymy. One feature is that the middle and lower reaches of the Yangtze River had the lowest values of isonymy at both the provincial and county levels. The second feature is that most counties with the highest values of isonymy were distributed in the provinces with high proportions of ethnic minorities. According to the dendrogram of surname distances, several clusters could be identified. Most provinces in a cluster were conterminous with one another. The one exception could be explained by demic migration called "braving the journey to the northeast of China." Isolation by distance could be detected because the correlation coefficients between Nei's distance and the geographic distances at the provincial, prefectural, and county levels were 0.64, 0.43, and 0.37, respectively. Human behaviors in Chinese history that may have caused these results have been discussed, including cultural origin, migration, residential patterns, and ethnic distribution.

Effect of population size on genetic variation levels in Capparis spinosa (Capparaceae) detected by RAPDs

Background: The population size of plants affects on population genetic variation. Materials and Methods: We studied the impact of population size on genetic variation in populations of Capparis spinosa (caper, Capparaceae) using RAPDs in East Azerbaijan (Iran). Withinpopulation genetic diversity was estimated based on Nei's and Shannon's diversity using Popgen, and genetic similarity among the populations was studied from a UPGMA dendrogram based the matrix of Nei's distances obtained through SHAN. Difference in the level genetic variation between small-sized and large-sized populations was tested using Mann-Whitney U test, and correlation between geographical and genetic distances among populations was examined by Pearson test (SPSS, 11.3). Total genetic variation was partitioned into within and among populations based on AMOVA using Arlequin. Results: The polymorphism levels of RAPDs bands among the populations ranged from 48.8% to 81.4%, and within-population Nei's diversity varied from 0.1667 to 0.2630. Genetic variation in smallsized populations (0.1667 to 0.1809) was significantly lower than the variations in large-sized populations (0.2158 -0.2630) (N= 7, P 0.674, Pearson correlation test). Conclusions: Population size has a dramatic impact on its genetic diversity. The results revealed that fragmentation of caper population in the study region has most likely occurred recently. The low genetic diversity revealed within caper populations indicates high risk of extinction and suggests that urgent conservation action is needed to recover diversity in these populations.

Validation of the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) in Age-Related Macular Degeneration

Patient-reported measures of visual function are increasingly incorporated into clinical trials of new treatments for age-related macular degeneration (AMD). Limited information is available regarding the associations between distance visual acuity (VA), reading speed, or contrast sensitivity and the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) subscales judged relevant to these measures. This study's objective was to evaluate such associations along with questions on restricted activity days. This cross-sectional study was conducted in patients with clinical diagnoses of neovascular AMD. Patient-reported outcome measures included the NEI VFQ-25 and restricted activity days. Clinical assessments included best-corrected visual acuity (BCVA), reading speed, and contrast sensitivity. The better-seeing eye was defined based on the BCVA of each patient. Psychometric properties of the NEI VFQ-25 were examined; analyses a priori focused on the Near Activities, Distance Activities, and Vision-Specific Dependency subscales. The final study group included 92 participants (mean age, 78 years). Cronbach's α for the subscales ranged from 0.67 to 0.92. The NEI VFQ-25 overall composite, Near Activities, Distance Activities, and Vision-Specific Dependency scores were correlated with BCVA (r = -0.48 to -0.54, all P < 0.0001), reading speed (r = 0.43 to 0.56, all P < 0.0001), and contrast sensitivity (r = -0.39 to -0.46, all P < 0.001) of the better-seeing eye and with restricted activity days (r = -0.52 to -0.55, all P < 0.0001). This study provides additional evidence supporting the validity of the NEI VFQ-25 in neovascular AMD patients by demonstrating correlations with a spectrum of vision measurements and a daily function measure.

Population structure and phylogeography of Toda buffalo in Nilgiris throw light on possible origin of aboriginal Toda tribe of South India

We report the genetic structure and evolutionary relationship of the endangered Toda buffalo of Nilgiris in South India with Kanarese and two other riverine buffalo breeds. The upgma phylogeny drawn using Nei's distance grouped South Kanara and Toda buffaloes at a single node while Marathwada and Murrah together formed a separate node. Principal component analysis was performed with pairwise interindividual chord distances which revealed clustering of Murrah and Marathwada buffaloes distinctly, while individuals of Toda and South Kanara breeds completely intermingled with each other. Furthermore, there were highly significant group variances (p < 0.01) when the breeds were grouped based on phylogeny, thus revealing the existence of cryptic genetic structure within these buffalo breeds. To know the evolutionary relationship among these breeds, 537-bp D-loop region of mitochondrial DNA was analysed. The phylogenetic analysis of mtDNA haplotypes following NJ algorithm with Chinese swamp buffalo as outgroup revealed a major cluster that included haplotypes from all the four investigated breeds and two minor clusters formed by South Kanara and Toda haplotypes. Reduced median network analysis revealed haplotypes of South Kanara and Toda to be quite distinct from the commonly found haplotypes indicating that these might have been ancestral to all the present-day haplotypes. Few mutations in two of the haplotypes of South Kanara buffalo were found to have contributed to ancestral haplotypes of Toda buffalo suggesting the possible migration of buffaloes from Kanarese region towards Nilgiris along the Western Ghats. Considering the close social, economic and cultural association of Todas with their buffaloes, the present study supports the theory of migration of Toda tribe from Kanarese/Mysore region along with their buffaloes.

Long-term human impacts on genetic structure of Italian walnut inferred by SSR markers

Life history traits, historic factors, and human activities can all shape the genetic diversity of a species. In Italy, walnut (Juglans regia L.) has a long history of cultivation both for wood and edible nuts. To better understand the genetic variability of current Italian walnut resources, we analyzed the relationships among the genetic structure of local walnut populations (inferred by SSR markers) and human migrations along ancient routes, using the territory of Royal Tratturo Candela-Pescasseroli (RT) as a case study. Sixteen J. regia provenances were collected along RT and compared with 13 Italian provenances and the landrace Sorrento. Although the level of SSR polymorphism we observed was moderately high, AMOVA revealed that most of the diversity was located within individuals (92.58%), and geographical differentiation was low (Dest = 0.076). Evidence for human-mediated domestication bottleneck events was detected in about 95% of walnut provenances. A Bayesian approach divided 456 walnut samples into three clusters: (1) Sorrento genotypes, (2) trees from the island of Sicily, and (3) the remaining germplasm. The UPGMA tree based on Nei's distances distinguished northeastern provenances and weakly grouped 12 of 16 provenances of RT. The observed genetic differences derived mainly from gradations in allele frequencies. Separation of the Sicilian provenance from the mainland may be explained in terms of founder effects and prolonged geographic isolation. Two contrasting forces, selection, and frequent inter-regional transfer of propagules, appear to drive the patterns of genetic variability for J. regia.

English

&nbsp; Genetic variation in three Iranian pelt sheep breeds namely: Gray Shiraz, Zandi and Karakul were investigated using fifteen microsatellite loci.&nbsp;Genomic DNA was extracted from 360 blood samples by extraction kits and salting-out procedure with some modifications. The total number of alleles ranged from 6 to12 in loci. The fifteen tested loci were all polymorphic in the three breeds. The average direct count of heterozygosity overall loci in each tested breed was more than the expected heterozygosity. Tests of genotype frequencies for deviation from the Hardy-Weinberg equilibrium (HWE) were performed at each locus of overall breeds and revealed significant departure from HWE (P &lt; 0.001) due to heterozygote excess.Polymorphism information content value&nbsp;in&nbsp;Gray Shiraz, Zandi and Karakul&nbsp;were 0.815, 0.808 and 0.808,&nbsp;respectively.&nbsp;Rate of inbreeding within the three breeds was not noticeable (global Fis&nbsp;= - 0.19). Low genetic differentiation was detected by estimation of Fst&nbsp;index between all pairs of breeds. Results showed that high level of genetic diversity was observed in pelt sheep. The phylogenetic tree based on Nei distances were drown using the neighbor-joining (NJ) and unweighted pair-group method using an arithmetic average (UPGMA). With both methods, Gray Shiraz and Karakul sheep populations were located together at one cluster and Zandi sheep population at another.&nbsp;The results can be useful in the development of breeding strategy for genetic improvement of pelt sheep in Iran. &nbsp; Key words:&nbsp;Microsatellites, sheep, genetic, diversity.

First Report of Stem Rot on Hosta plantaginea caused by Sclerotium rolfsii in Korea

A stem rot disease caused by Sclerotium rolfsii sporadically afflicted fragrant plantain lily (Hosta plantaginea Aschers.) from 2008 to 2010 in the herb exhibition garden at Gangju Pond, which is located in Jeongchon-myon, Jinju, Korea. The fragrant plantain lilies, which are perennial plants grown in home gardens, recently were planted en mass in parks and public gardens for ornamental purposes, where they form dense communities. During summer, the stems of the plants under the canopy are exposed to warm temperatures and high humidity, which favor disease development. The disease developed mainly on stems near the soil line. Infected stems gradually died, and white mycelial mats appeared on the stem surfaces (Fig. 1A). Often, numerous sclerotia were produced on stem surfaces near the soil line. The heavily infected stems became rotted and blighted, and the whole plant eventually died. The freshly isolated pathogenic fungus grown on potato dextrose agar (PDA) was examined microscopically and culturally. The optimal growth temperature on PDA was 30°C. Aerial mycelia usually formed many narrow hyphal strands 3-9 μm wide. The white mycelium had a typical clamp connection structure for 4 days after growth at optimum temperature (Fig. 1D). Small globoid sclerotia formed abundantly on the PDA after 20 days of mycelial growth (Fig. 1C). The sclerotia, which were relatively uniform in size at 1-3 mm, were white at first, and then turned dark brown. The maximum number of sclerotia was produced at 25-30 oC. To test pathogenicity, inoculums were prepared with mycelial mats and mixed with autoclaved soil. Then, soil inoculums containing mycelial mats were artificially inoculated onto Hosta plantaginea. The same fungal fruiting symptoms were reproduced, and the fungus was re-isolated based on these symptoms (Fig. 1B). To identify the causal fungus, we amplified and sequenced a partial internal transcribed spacer (ITS) rDNA region of the isolate using the primers ITS1 and ITS4, as described by White et al. (1990). The resulting sequence of 684-bp was deposited in GenBank (accession no. HM355751). Phylogenetic analysis was performed using MEGA4 software, with the neighbor-joining method and Tajima–Nei distance model. Previously published ITS sequences of S. rolfsii strains were included for reference, and S. cepivorum was used as the outgroup (Harlton et al., 1995). Neighbor-joining analysis showed that the two species had similar ITS sequences (Fig. 2). In the phylogenetic tree (Fig. 2), the isolate was placed within a clade comprising reference isolates of S. rolfsii.

Characterization of Casein Gene Complex and Genetic Diversity Analysis in Indian Goats

Milk protein polymorphism plays an important role in genetic diversity analysis, phylogenetic studies, establishing geographical diversity, conservation decision, and improving breeding goals. Milk protein polymorphism in Indian goat breeds has not been well studied; therefore, an investigation was carried out to analyze the genetic structure of the casein gene and milk protein diversity at six milk protein loci in nine Indian goat breeds/genetic groups from varied agro-climatic zones. Milk protein genotyping was carried out in 1098 individual milk samples by SDS-PAGE at αS1-CN (CSN1S1), β-CN (CSN2), αS2-CN (CSN1S2), κ-CN (CSN3), β-LG, and α-LA loci. Indian goats exhibited αS1-casein A allele in higher frequency in the majority of breeds except Ganjam and local goats. The αS1-casein A allele frequencies varied from 0.45 to 0.77. A total of 16 casein haplotypes were observed in seven breeds and breed specific haplotypes were observed with respect to geographic region. The average number of alleles was lowest in Ganjam (1.66 ± 0.81) and highest in Sirohi goats (2.50 ± 1.05). Expected heterozygosity at six different loci demonstrated genetic diversity and breed fragmentation. Neighbor-Joining tree was built basing on Nei's distance. There was about 16.95% variability due to differences between breeds, indicating a strong subdivision. Principal component analysis was carried out to highlight the relationship among breeds. The variability among goat breeds was contributed by αS2-CN, β-LG and αS1-CN. The Indian goats exhibited αS1-CN (CSN1S1) A allele in higher frequency in all the breeds indicating the higher casein yield in their milk.

Genetic diversity of captive spotted paca (Agouti paca) from south east Brazil assessed by the RAPD-PCR technique

The genetic diversity was analyzed among spotted paca (Agouti paca) from three commercial flocks located in Brazil. As the genome of this species is unknown, the RAPD-PCR technique was used. Ten primers generated sixty polymorphic bands. The among and within population genetic variability estimated by analysis of molecular variance (AMOVA) was 12.55 and 87.45%, respectively. The shortest Nei distance value was 11.76% among the Carangola (CG) and São Francisco do Glória (SF) populations. This value can be explained by the exchange of reproduction males and females between the two geographically close breeding sites. The analysis of principal components showed well defined and structured groups aggregating animals according their population of origin, with some exceptions. Lower diversity was found in the São Francisco population than in the Carangola and Castelo (CS) populations. This result suggested the variability is better conserved in breeding farms with fifty or sixty animals (CG and CS) than in the breeding farm with a dozen animals (SF). The RADP-PCR technique proved to be informative for the quantification of among and within population genetic variability of the spotted paca. The phenogram generated by UPGMA using the NTSYS-PC software from the Nei Distance, grouped CG and SF on a single branch connected to the CS, with 76 and 100% accuracy, respectively, to the bootstrap. This result was not only consistent with the historical and geographical information on flocks, but also shows the need for periodic reproductive male replacement. Future studies should be developed with co-dominant markers and include spotted paca from more distant places.

Morphological and Genetic Variations in Vendace (Coregonus Albula(L.)) in the Lakes of Lithuania

Morphological and genetic variations in the vendace, Coregonus albula, in 31 lakes of Lithuania were investigated. Twenty one morphometric and six meristic characters, as well as eight loci of three isoenzyme systems and one nonspecific protein, were analysed. No intraspecific groups of vendace were identified in the investigated lakes. The obtained results showed that interpopulation differences in vendace are not associated with geographic distances between lakes and the location of lakes in the hydrographic system of Lithuania. Some morphometric and meristic characters were found to correlate with morphological parameters of the lakes, but no significant correlation was observed between Nei distances and other interpopulation parameters. Vendace populations of the southern part of Lithuania are the most distinctive among other investigated vendace populations.

Quantification of the genetic change in the transition of Rhodnius pallescens Barber, 1932 (Hemiptera: Reduviidae) from field to laboratory

Previous studies have reported genetic differences between wild-caught sylvatic, domestic and laboratory pop-ulations of several Triatominae species. The differences between sylvatic and laboratory colonies parallel are similar to the differences observed between sylvatic and domestic populations. Laboratory colonies are frequently used as references for field populations, but the consequences of founder events on the genetic makeup of laboratory or domestic populations are rarely quantified. Our goal was to quantify the genetic change in Rhodnius pallescens populations artificially submitted to founder effects via laboratory colonization. We compared the genetic makeup of two sylvatic populations and their laboratory descendants using a panel of 10 microsatellite markers. Both sylvatic populations were initially collected from palm trees, but the colonies differed in the number of founder insects and amount of time kept in the laboratory. We evaluated allelic polymorphism, differences between expected and observed heterozygosity, estimates of population differentiation (Fst) and inbreeding (Fis, Fit) and cluster analyses based on Nei's distances. We found a unique genetic structure for each sample population, with significant differentiation between the field insects and each of the laboratory generations. These analyses showed strong founder effects and showed that genetic drift had led to a genetic equilibrium over several generations of isolation. Our results suggest that laboratory colonies of R. pallescens have a different genetic structure than their wild relatives and similar processes likely affect other Triatominae laboratory stocks.

Allozyme and morphology evolution in European Viviparidae (Mollusca: Gastropoda: Architaenioglossa)

The paper describes morphometric and allozymic differences among four European species of the family Viviparidae: Viviparus contectus (Millet, 1813), V. viviparus (Linnaeus, 1758), V. acerosus Bourguignat, 1862, and V. ater (Cristofori et Jan, 1832). Fourteen continuous biometrical characters were measured. Incremental discriminant-function analysis, principal-component analysis, and non-metric multidimensional scaling were applied to analysis of the morphometric differences. All the techniques confirmed a similar picture: a slight morphometric differentiation, with the variability ranges of the species overlapping. On the other hand, the allozymic differentiation, studied at 12 loci, eight of them intra and/or interspecific polymorphic, is much better marked, the intraspecific Nei's distances among the four V. contectus populations ranging from 0.0014 to 0.0397, mean 0.0166, and interspecific distances ranging from 0.2306 (V. ater–V. acerosus) to 0.9888 (V. contectus 2 and V. viviparus), mean 0.6871. The allele frequencies and genetic distances (Nei's distance and Cavalli-Sforza and Edwards’chord distance) were used to compute maximum likelihood, additive Fitch–Margoliash and ultrametric Fitch–Margoliash trees. All the trees presented a similar pattern, but the maximum-likelihood and additive trees, based on Cavalli-Sforza and Edwards’distance, seem to reflect the phylogeny best. The results are compared with the most parsimonious phylogenies inferred for radular, soft-part morphology and anatomy, and opercular data from other papers by us, and the inferred phylogenies are also compared. Although the inferred molecular and morphological phylogenies are little different in topology, the amount of evolution along the corresponding branches (measured as the number of changes averaged over all reconstructions) is very different, the value of correlation coefficient between the two phylogenies being statistically insignificant. The occurrence of interspecific hybrids is discussed, and the isolation-by-competition mechanism is postulated. The probable origin of V. viviparus from a founder population extremely restricted in number is stressed. The possible history of the group is briefly discussed. The species is suggested to have originated in an unusual habitat of melt water at a glacier foreland that could have promoted genotypic differentiation and sympatric speciation.

Surnames in Siberia: A study of the population of Yakutia through isonymy

We studied the isonymic structure of the Republic of Sakha (Yakutia), in the Russian Federation, using the surname distributions of 491,259 citizens above 18 years registered as residents in 2002. These were distributed in 35 districts and 497 towns and settlements of the Republic. The number of different surnames was 44,625. Matrices of isonymic distances between the 35 districts were tested for correlation with the geographic distance between the population centers of gravity of the districts. We found that, for the whole of Yakutia, Nei's distance was correlated with geographic distance (r = 0.693 +/- 0.027). A dendrogram of the 35 districts was built from the distance matrix, using the UPGMA method. The clusters identified by the dendrogram correlate with the geographic position of the districts. The correlation of random inbreeding calculated from isonymy, F(ST), with latitude was positive and highly significant but weak (r = 0.23). So, inbreeding was highest in the Arctic districts, and lowest in the South. Average alpha for 497 towns was 107, for 35 districts it was 311, and for the Republic 433. The value of alpha was higher for Russian than for the local languages. The geographical distribution of alpha, high in the Center and South-East and lower in the North-West, is compatible with the settlement of groups of migrants moving from the South-East toward the center and the North of Yakutia. It is proposed that low-density demic diffusion of human populations results in high inbreeding and may have been a general phenomenon in the early phases of human radiations.

Taxonomic status of two South American sympatric squat lobsters, Munida gregaria and Munida subrugosa (Crustacea: Decapoda: Galatheidae), challenged by DNA sequence information

We investigated the taxonomic status of two sympatric morphospecies of squat lobsters from southern South America (Beagle Channel, Strait of Magellan, and Burdwood Bank), Munida gregaria and Munida subrugosa, by DNA sequence analysis of three mitochondrial (mt)DNA gene fragments [416 bp of 16S rDNA(165), 566 bp of cytochrome c oxidase subunit I(COI) and 418 bp of NADH dehydrogenase subunit 1 (ND1)]; and the nuclear rDNA internal transcribed spacer (ITS) 1 (883–952 bp). We obtained a total of 79 sequences from 32 individuals. The 16S sequences of all M. gregaria and M. subrugosa were invariant and identical, whereas COI and ND1 showed 12 and 15 variable sites, respectively. These polymorphisms were shared between morphospecies. Interspecific Tamura–Nei distances for COI and ND1 sequences were 0.0024 and 0.0032, respectively, and were not significantly different from intraspecific distances (Kruskal–Wallis tests: P = 0.58 and P = 0.69, for COI and ND1, respectively). Similar to the results obtained from the mtDNA sequences, no relationship was found between the ITS1 maximum parsimony tree topology and the morphologic classification of specimens in M. gregaria and M. subrugosa. We conclude that M. gregaria and M. subrugosa from southern South America may either represent a case of a dimorphic species, or a case of incomplete lineage sorting. The fact that these two morphospecies did not show fixed differences over a total of 1947 bp analysed reinforces the hypothesis of a single dimorphic species. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 421–434.

Genetic diversity of Brazilian Pantaneiro horse and relationships among horse breeds

The objective of this work was to evaluate the genetic diversity of Brazilian Pantaneiro horse by microsatellite markers, investigate the effect of genetic bottlenecks and estimate genetic differentiation among four horse breeds. Genetic variation was estimated through allele frequencies and mean breed heterozygosity. Nei's genetic distances among the breeds Pantaneiro, Thoroughbred, Arabian, Spanish Pure Breed (Andalusian), and Uruguay Creole were calculated, and it was used to construct an UPGMA dendrogram. Clustering at different K values was calculated to infer population structure and assign individuals to populations. Nei's distances showed a minimum distance between Pantaneiro horse and Spanish Pure Breed (0.228), and similar distances from Spanish Pure Breed to Thoroughbred and to Arabian (0.355 and 0.332). It was observed a great level of diversity, clear distance from Pantaneiro horse to other breeds, and genetic uniformity within breed. It was verified a certain level of substructure of Pantaneiro horse showing no influences from the other studied breeds.