Genetic diversity of natural populations of Taxus mairei

Taxus mairei (Lemée & Lév.) S.Y. Hu ex T. S. Liu is a vulnerable tree species, and it is also a precious timber species in China. We used 13 microsatellites to assess the genetic diversity and differentiation of 665 T. mairei samples from 18 natural populations. A total of 291 alleles were detected. The average number of alleles (N_a?=?22.39), expected heterozygosity (H_e?=?0.74), polymorphic information content (PIC?=?0.86) and Shannon diversity index (I?=?1.66) of the loci indicated a high level of genetic diversity in natural T. mairei populations. Moreover, gene flow was more active among populations (N_m?=?1.62) than within populations. Among the 18 populations, the Xinfeng population in Jiangxi Province has the highest genetic diversity. Although each of the studied populations should be protected from further deforestation and agricultural expansion, the Xinfeng population deserves the highest conservation priority. The results based on analysis of molecular variance showed that genetic variation occurred mainly within populations (84.90%; P?<?0.001), which indicated that the degree of genetic differentiation of the natural populations of T. mairei was low. Based on UPGMA, the 18 populations were categorized into two groups. A Mantel test showed that there was no significant correlation between standard genetic distance and geographical distance or altitude differences among the populations. The genetic clustering results also indicated that there are varying degrees of gene penetration among natural populations of T. mairei. The information presented here forms the basis for the development of genetic guidelines for appropriate conservation programs.

     

Morphometric analysis of disjunctPapaver radicatum (Papaveraceae) populations in southern Norway

Morphometric relationships between populations ofPapaver radicatum within the southern Norwegian mountains were investigated using canonical variates analysis andWard's clustering on capsule and leaf character sets. The survey describes patterns of variation among 13 wild-scored populations from five geographically disjunct localities, usually assigned to five races or subspecies. Our results from wild-collected material largely support earlier findings based on univariate statistics on cultivated material. In general, populations from within a disjunct locality (=subspecies) are most similar to other populations from the same locality. However, the subspecies vary in the degree to which they are differentiated in capsule morphology. The subsp.groevudalense populations are morphologically close to the main group of subsp.ovatilobum populations. Subspp.intermedium andoeksendalense are clearly distinct from one another and from the other subspecies, whereas the single subsp.gjaerevolli population is more similar to theovatilobum/groevudalense complex. Variation in leaf characters showed only partial congruence with variation in capsule characters. The pattern of morphological relationships among the subspecies is thus more complex than previously thought. The subspecies may have become differentiated during a period of isolation, but such results alone cannot indicate the duration of such a period.     

Notes on Algerian aquatic fungi: Pythium pythioides

Pythium pythioides (Roze & Cornu) Ramsbottom is recorded from Algeria. Since its original discovery in 1869 this species had not been found back. A brief history is given and morphological and reproductive characters are discussed.     

Speciation inVirgilia (Fabaceae): Allopatric divergence followed by introgression?

Levels of variation revealed by starch gel-electrophoresis were compared with morphological and chemical variation within and among the species and subspecies ofVirgilia:V. oroboides subsp.oroboides, V. oroboides subsp.ferruginea andV. divaricata. The data sets exhibited concordance in that all point to a very close relationship between the taxa. Differences are mostly quantitative and an overlapping east-west gradient of character variation is indicated. Analysis of morphological and chemical characters showed thatV. oroboides subsp.ferruginea andV. divaricata are relatively distinct, whereas allozyme analysis indicated a high degree of genetic similarity among populations of these two taxa. The observed pattern of variation suggests relatively recent speciation with subsequent introgressive hybridisation resulting in a geographical and ecological gradient.     

A revision of the <Emphasis Type="Italic">Heterospathe elegans</Emphasis> (<Emphasis Type="Italic">Arecaceae</Emphasis>) complex in New Guinea

Summary  Three closely affiliated species of Heterospathe Scheff. (H. elegans (Becc.) Becc., H. humilis Becc. and H. versteegiana Becc.) from New Guinea are revised. They are reduced to a single species which is divided into two subspecies, and the new combination H. elegans subsp. humilis (Becc.) M. S. Trudgen & W. J. Baker is made. The subspecies can be readily distinguished by their growth habit. Epitypes are designated for the three previously published names, as informative material on the habit is not included in the existing type specimens. A new, potentially related species is described as H. pullenii M. S. Trudgen & W. J. Baker.     

Gene flow in admixed populations and implications for the conservation of the Western honeybee, Apis mellifera

Anthropogenic activity, especially modern apiculture, has considerable impact on the natural distribution of the Western honeybee, Apis mellifera, leading to the spread, replacement and fragmentation of many subspecies. This creates demand for the conservation of some subspecies, in particular, Apis mellifera mellifera, which once was widely distributed in Western Europe and nowadays is endangered through habitat loss and fragmentation. Moreover, A. m. mellifera may be further endangered by hybridisation in populations that now occur in artificial sympatry with other subspecies. Here, we quantify and compare individual hybridisation between sympatric and allopatric honeybee populations of A. m. mellifera and A. m. carnica using microsatellite markers and a Bayesian model-based approach. We had a special focus on pure breeding populations, which are a major tool in honeybee conservation. Our results demonstrate that subspecies are still highly differentiated, but gene flow is not prevented by the current management strategies, creating urgent demand for an improved conservation management of A. m. mellifera. However, the occurrence of a high number of pure individuals might suggest that some sort of hybrid barrier acts against the complete admixture of the two subspecies.     

On the knowledge of the geographic variation of the satyrid <Emphasis Type="Italic">Oeneis jutta</Emphasis> (Hübner, [1806]) (Lepidoptera,Satyridae) in the Northeast of European Russia

Analysis of the geographic variation of external characters of the satyrid Oeneis jutta (Lepidoptera, Satyridae) in the northeast of European Russia was carried out. Variation of the forewing length, diameter of eyespots, their total number and frequency of occurrence on the upper side of wings were studied. The regional populations of Oe. jutta were shown to lack significant differences in the characters studied. Besides the similarity of external characters, similar ecological traits also suggest that Oe. jutta populations from the northeast of European Russia belong to the nominative subspecies. The probable history of distribution of Oe. jutta across Europe also suggests that the nominative subspecies occurs in the territory studied.     

Ecotype differentiation and coexistence of two parapatric tetraploid subspecies of cocksfoot (Dactylis glomerata) in the Alps

Two tetraploid subspecies of Dactylis glomerata L., subsp. reichenbachii (Hausm.) Stebbins et Zohary and subsp. glomerata , occur in the French Alps. The former is confined to dolomitic, south-facing, alpine lawns above 2000 m, whereas the latter occurs in non-dolomitic habitats in subalpine meadows mainly below 1900 m. Previous studies of allozyme variation have shown that genetic introgression between the two subspecies occurs over large areas. By contrast, morphologically intermediate individuals only occur in an extremely narrow area, suggesting that the morphological and physiological differences between the two subspecies is of adaptive significance. A reciprocal clone transplant experiment was set up to examine (1) any genetic differences between subspecies indicative of ecotypic differentiation in relation to habitat characteristics and (2) the level of phenotypic plasticity in the two subspecies. Genetic differentiation was confirmed by a statistically significant taxon × site interaction effect in anova for all traits studied. The glomerata populations produced more tillers, longer leaves and higher culms in all sites, especially in their home environment. However, reichenbachii populations produced more seeds than the glomerata populations in the original reichenbachii environment, suggesting ecotypic differentiation between the two subspecies. This result might also explain why the glomerata subspecies is unable to colonize dolomitic habitats occupied by the reichenbachii subspecies. The reichenbachii populations showed less plasticity than the glomerata populations for leaf length and floriferous tiller number, a result which is discussed in the context of the response of plants from productive and non-productive habitats to environmental variation.     

Biometrical variability of foliage and cone characters inCupressus bakeri (Cupressaceae)

Biometrical variability of foliage, cones, and seeds were analyzed in 8 native populations (throughout the range) of a relictual species,Cupressus bakeri Jeps. (Cupressaceae) from California and Oregon. The partition of variation within and among populations for this rare plant was investigated and the justification for subspecies status was reviewed. Morphological characters varied significantly, with more of the variation among populations than at the population level. Multivariate analyses indicated close affinities among populations on serpentine sites suggesting the presence of a serpentine race. However, the high degree of variation among populations did not permit their clear separation into the two subspecies described byWolf (1948). We conclude thatC. bakeri should be treated as a monotypic species.     

A rapid PCR-based diagnostic test for the identification of subspecies of <Emphasis Type="Italic">Acacia saligna</Emphasis>

Subspecific taxa of species complexes can display cryptic morphological variation, and individuals and populations can often be difficult to identify with certainty. However, accurate population identification is required for comprehensive conservation and breeding strategies and for studies of invasiveness and gene flow. Using five informative microsatellite markers and a Bayesian statistical approach, we developed an efficient polymerase chain reaction-based diagnostic tool for the rapid identification of individuals and populations of the Acacia saligna species complex of Western Australia. We genotyped 189 individuals from 14 reference populations previously characterised based on morphology and used these data to investigate population structure in the species complex. High total genetic diversity (H _T = 0.729) and high population differentiation (θ = 0.355) indicated strong intraspecific structuring. With the provision of prior population information, the reference data set was optimally resolved into four clusters, each corresponding to one of the four main proposed subspecies, with very high membership values (Q > 97%). The reference data set was then used to assign individuals and test populations to one of the four subspecies. Assignment was unequivocal for all test individuals from two populations of subsp. lindleyi and for all but one individual of subsp. stolonifera. Individuals from populations of subsp. saligna and subsp. pruinescens showed a degree of genetic affinity for the two subspecies in their assignments, although the majority of individuals were correctly assigned to subspecies. The diagnostic tool will assist in characterising populations of A. saligna, especially naturalised and invasive populations of unknown origin.     

Morphological and genetic analysis of the Red Hills roach (Cyprinidae: Lavinia symmetricus)

We performed a morphological and phylogeneticanalysis of a recently discovered population ofCalifornia roach (Red Hills roach; Cyprinidae:Lavinia symmetricus) to determine if thedegree of separation of these populationswarrants subspecies status. Previousmorphological analysis by Brown et al. (1992)suggested that L. symmetricus from theRed Hills roach type locality (Horton Creek)were different for Principal DiscriminantScores (based on 15 morphological characters)from neighboring populations. Similarly,recent work by our lab on the phylogenetics ofthe putative subspecies of L. symmetricushas revealed that the Red Hills roach appearsreciprocally monophyletic for assayedmitochondrial DNA markers. In addition toperforming further morphological and geneticanalysis of the Red Hills roach, we increasedour sampling effort in the Red Hills region todetermine the distribution of this undescribedputative subspecies. Our morphological resultsare generally in agreement with Brown et al.(1992) except in regards to Horton Creek. Asignificant difference between the two studiesexists for all Horton Creek multivariateanalyses as well as frequency of a presumablyderived character (chisel lip). Our geneticresults also support our previous findings thatthe Red Hills roach is a diagnosible,genetically distinct population. Thephylogenetic analysis suggests that populationson the other side of a large reservoir wererecently connected via gene flow to the RedHills populations.     

Fine structure and function of ocelli and sagittocysts of acoel flatworms

We studied the taxonomy and distribution of the Conchostraca in Yugoslavia. A diverse fauna occurs in the country. However, the systematics of this group is still incomplete and has many problems. There is considerable variability of morphological characters. By a comparative-morphological analysis of the populations found, we re-evaluated the taxonomic significance of a series of structural characters, and offer comments on the results.In Yugoslavia four families were found: Cyzicidae Stebbing, 1910; Limnadiidae Burmeister, 1843; Imnadiidae Botnariuc & Orghidan, 1941 and Leptestheriidae Daday, 1923, with a present total of 8 species and 4 subspecies. Within the genus Imnadia Hertzog, 1935, three new species were found: Imnadia cristata Marinek, 1972; Imnadia banatica Marinek & Valvajter, 1982 and Imnadia panonica Marinek & Petrov, 1984. Within the genus Eoleptestheria Daday, 1923, the species Eoleptestheria spinosa Marinek, 1978, with four distinct subspecies was discovered.     

Population structure and genetic diversity distribution in wild and cultivated populations of the traditional Chinese medicinal plant Magnolia officinalis subsp. biloba (Magnoliaceae)

Magnolia officinalis subsp. biloba, a traditional Chinese medicinal plant, experienced severe declines in the number of populations and the number of individuals in the late 20th century due to the widespread harvest of the subspecies. A large-scale cultivation program was initiated and cultivated populations rapidly recovered the loss in individual plant numbers, but wild populations remained small as a consequence of cutting. In this study, the levels of genetic variation and genetic structure of seven wild populations and five domestic populations of M. officinalis subsp. biloba were estimated employing an AFLP methodology. The plant exhibited a relatively high level of intra-population genetic diversity (h = 0.208 and H _j = 0.268). The cultivated populations maintained approximately 95% of the variation exhibited in wild populations, indicating a slight genetic bottleneck in the cultivated populations. The analysis of genetic differentiation revealed that most of the AFLP diversity resided within populations both for the wild group (78.22%) and the cultivated group (85.92%). Genetic differentiation among populations in the wild group was significant (F _ST = 0.1092, P < 0.005), suggesting wild population level genetic structure. Principal coordinates analysis (PCO) did not discern among wild and cultivated populations, indicating that alleles from the wild population were maintained in the cultivated gene pool. Results from the present study provide important baseline data for effectively conserving the genetic resources of this medicinal subspecies.     

贵州特有植物长柱红山茶种群年龄结构及空间分布格局研究

为评估贵州特有植物长柱红山茶(Camellia mairei var.lapiden)的资源现状,采用样方法对其种群年龄结构和空间分布格局进行了研究。结果表明,长柱红山茶种群年龄结构为衰退型,种群密度以中龄树>老年树>幼龄树;不同发育阶段种群的空间分布格局不同,幼龄树和中龄树均呈显著集群分布,老年树接近集群分布或随机分布;种群的3个发育阶段之空间关系不密切,均表现为负相关或不相关。长柱红山茶由于其繁殖生物学特性和受其群落之种内、种间竞争及生境异质性的影响而趋于濒危和灭绝。因此,建立长柱红山茶就地保护区和开展引种栽培,扩大其栽培种植范围以增加种群数量是保护长柱红山茶种质资源的有效措施。     

Inferring the roles of vicariance,climate and topography in population differentiation in Salamandra algira (Caudata,Salamandridae)

Integrating information from species occurrence data, environmental variables and molecular markers can provide valuable insights about the processes of population persistence and differentiation. In this study, we present the most comprehensive overview of the evolutionary history of the North African salamander Salamandra algira (Caudata, Salamandridae) to date, including analyses of climatic and topographical variables, and sequences of two mitochondrial and two nuclear DNA fragments, with a special focus on Algerian populations, under‐represented in previous studies. Coalescent‐based phylogenetic analyses of mtDNA data recover four well‐supported population groups corresponding to described subspecies, with a western clade including populations in north‐western Morocco (with two subclades corresponding to the subspecies tingitana and splendens), and an eastern clade including populations from north‐eastern Morocco (subspecies spelaea) and Algeria (subspecies algira). Inferred split times between major clades date back to the Miocene, with additional splits within each major clade in the Plio‐Pleistocene. Present climatic (aridity) and topographical factors account for geographical discontinuities across population groups and help identify potential areas of secondary contact between clades corresponding to the subspecies tingitana and splendens in the Rif mountains in Morocco. Niche analysis indicates the absence of phylogenetic signal in the use of environmental space in this species.     

Genetic introgression between tetraploidDactylis glomerata subspp.reichenbachii andglomerata in the French Alps. Insight from morphological and allozyme variation

The morphology, phenology and allozyme polymorphism in seven tetraploidDactylis glomerata populations growing in the French Alps were studied. Based on habitat and morphological characteristics, two of the populations could be classified asD. glomerata subsp.reichenbachii, which is known to comprise diploid and tetraploid plants growing exclusively on dolomite, on south-facing meadows. This subspecies has been previously recorded in the Italian and Swiss Alps but not in the French Alps. The remaining five populations were morphologically intermediate but more similar to the cosmopolitanD. glomerata subsp.glomerata. On the basis of allozyme variation, all populations were more related to subsp.reichenbachii than to the cosmopolitan subsp.glomerata, suggesting that gene flow has occurred between the two tetraploid subspecies. The possibility that selection has acted differently on morphological and allozyme characters is discussed.     

Molecular and phenotypic diversity in Chionactis occipitalis (Western Shovel-nosed Snake), with emphasis on the status of C. o. klauberi (Tucson Shovel-nosed Snake).

Chionactis occipitalis (Western Shovel-nosed Snake) is a small colubrid snake inhabiting the arid regions of the Mojave, Sonoran, and Colorado deserts. Morphological assessments of taxonomy currently recognize four subspecies. However, these taxonomic proposals were largely based on weak morphological differentiation and inadequate geographic sampling. Our goal was to explore evolutionary relationships and boundaries among subspecies of C. occipitalis, with particular focus on individuals within the known range of C. o. klauberi (Tucson Shovel-nosed snake). Population sizes and range for C. o. klauberi have declined over the last 25 years due to habitat alteration and loss prompting a petition to list this subspecies as endangered. We examined the phylogeography, population structure, and subspecific taxonomy of C. occipitalis across its geographic range with genetic analysis of 1100 bases of mitochondrial DNA sequence and reanalysis of 14 morphological characters from 1543 museum specimens. We estimated the species gene phylogeny from 81 snakes using Bayesian inference and explored possible factors influencing genetic variation using landscape genetic analyses. Phylogenetic and population genetic analyses reveal genetic isolation and independent evolutionary trajectories for two primary clades. Our data indicate that diversification between these clades has developed as a result of both historical vicariance and environmental isolating mechanisms. Thus these two clades likely comprise ‘evolutionary significant units’ (ESUs). Neither molecular nor morphological data are concordant with the traditional C. occipitalis subspecies taxonomy. Mitochondrial sequences suggest specimens recognized as C. o. klauberi are embedded in a larger geographic clade whose range has expanded from western Arizona populations, and these data are concordant with clinal longitudinal variation in morphology.     

Genetic characterization of common carp (Cyprinus carpio) populations from Greece using mitochondrial DNA sequences

Wild common carp from two lakes and two rivers in Greece were genetically characterized with sequencing analysis of two mitochondrial DNA segments: cytochrome b (1119 bp) and D-loop (646 bp). A total of 9 variable singleton sites and 7 unique haplotypes were detected. A common haplotype was found in three out of the four populations examined, which seems to be the ancestral one and represents the European origin of common carp from Greece. This haplotype could be also justified by the introductions reported with individuals belonging to the Central European race, into many natural habitats in Greece. Limited genetic variation — in Evros and Aliakmonas populations — could be due to bottleneck effects and small effective population sizes, whereas the different haplotypes found in Lake Volvi could represent different common carp stocks. Values of sequence divergence among Greek haplotypes ranged from 0.0006 to 0.0023. The Neighbour-Joining (NJ) phylogenetic tree constructed based on the combined sequences, reveals that the populations of common carp from Greece belong to the European group of populations — which is highly divergent from the South East-Asia cluster — and to the subspecies Cyprinus carpio carpio.     

Population characteristics of endangered species Taxus chinensis var. mairei and its conservation strategy in Shanxi, China

The conservation of the endemic, endangered, and first-class protected tree species, Taxus chinensis var. mairei (Lem. & H. Lev.) W. C. Cheng & L. K. Fu, is urgent in China. To assist the protection of this important medicinal plant species, the biological and ecological characteristics of its populations were investigated and analyzed in Shanxi. The study area, southeastern Shanxi, is a special region suitable for this species growth and development. The floristic composition, life form spectrum, and species diversity of T. chinensis var. mairei forests reflected the features of both warm-temperate and subtropical regions. Size classes in DBH and static life table analysis showed that the population structure of T. chinensis var. mairei was of the increase-type. Plant density, survivorship, and mortality decreased with increase in age. Distribution patterns of individuals were basically clumped and saplings tended to be distributed randomly. Disturbance from collection of leaves, branches, and stems for medicine was an important factor affecting population structure, dynamics, and distribution. The sex ratio of female/male and the efficiency of sexual reproduction were very low. The main way of reproduction for this species is vegetative propagation. Based on these characteristics, some suggestions, such as establishing nature reserves, improving population structure by cultivation and transplantation, developing seed gardens, and plantations, etc., for the conservation management of T. chinensis var. mairei and its forests in Shanxi are discussed.     

Morphometric differentiation of the moor frog (Rana arvalis Nilss.) in Central Europe

Morphometric variation of 11 characters was studied in 14 samples of Rana arvalis from allopatric population groups in Central Europe, representing two subspecies formerly recognised: R. a. arvalis and R. a. wolterstorffi. All samples from Poland (nine) were collected from the area, which is believed to be populated by the nominal form. In addition, the isolated population of R. arvalis from the Eastern Carpathians of Romania was classified to that form. All the Hungarian samples fall into the range of R. a. wolterstorffi. No significant differences in body size between sexes and among the populations from the three geographic regions (Poland, Hungary and Romanian Eastern Carpathians) were found. Multivariate analysis of the differences in body shape among groups showed that the populations from Hungary differed from the nominal form mainly in the relative hindlimb length. However, substantial overlap in overall shape differences resulted in a relatively low percentage of correct classifications to the respective geographic groups in the Discriminant Analysis. Large intrapopulation variation in the values of the two ratios (SVL/TL and TL/IMT) formerly used for differentiate the two European subspecies of R. arvalis makes them unreliable characters for distinguishing the two forms. The pattern of morphometric variation does not match the overall genetic divergence of the R. arvalis populations, which suggests that the body shape differences in this species result from the phenotypic plasticity correlated with local climatic factors.