Genetic diversity across natural populations of <Emphasis Type="Italic">Dendrobium officinale</Emphasis>, the endangered medicinal herb endemic to China,revealed by ISSR and RAPD markers

Dendrobium officinale is a rare and endangered herb with special habitats and endemic to China. Genetic diversity was examined within and among nine natural populations using inter-simple sequence repeat (ISSR) and random amplified polymorphic (RAPD) for conservation. Both molecular markers revealed a high percentage (>89%) of polymorphic bands and ISSR markers detected more diversity than RAPD markers. Analysis of molecular variance (AMOVA) revealed that 78.84% (ISSR) and 78.88% (RAPD) of variability was partitioned among individuals within populations. This genetic structure was probably due to severe genetic drift resulting from habitat fragmentation and human overexploitation since 1950s. Moreover, there is a lack of significant association between genetic and geographic distances (r = 0.276; p > 0.05) in the populations of D. officinale. From the conservation point of view, populations GL, GS and GSD with higher genetic diversity should be protected firstly to maintain the species potential for evolutionary change and population YG with lower diversity but representing a novel evolutionary unit should also be paid more attention to during D. officinale conservation practice. Published in Russian in Genetika, 2009, Vol. 45, No. 3, pp. 375–382. The article is published in the original.     

Remnants fragments preserve genetic diversity of the old forest lichen <Emphasis Type="Italic">Lobaria pulmonaria</Emphasis> in a fragmented Mediterranean mountain forest

Fragmentation represents a serious threat to biodiversity worldwide, however its effects on epiphytic organisms is still poorly understood. We study the effect of habitat fragmentation on the genetic population structure and diversity of the red-listed epiphytic lichen, Lobaria pulmonaria, in a Mediterranean forest landscape. We tested the relative importance of forest patch quality, matrix surrounding fragments and connectivity on the genetic variation within populations and the differentiation among them. A total of 855 thalli were sampled in 44 plots (400 m²) of 31 suitable forest fragments (beeches and oaks), in the Sierra de Ayllón in central Spain. Variables related to landscape attributes of the remnant forest patches such as size and connectivity and also the nature of the matrix or tree species had no significant effects on the genetic diversity of L. pulmonaria. Values of genetic diversity (Nei’s) were only affected by habitat quality estimated as the age patches. Most of the variation (76%) in all populations was observed at the smallest sampled unit (plots). Using multiple regression analysis, we found that habitat quality is more important in explaining the genetic structure of the L. pulmonaria populations than spatial distance. The relatively high level of genetic diversity of the species in old forest patches regardless of patch size indicates that habitat quality in a highly structured forest stand determines the population size and distribution pattern of this species and its associated lichen community. Thus, conservation programmes of Mediterranean mountain forests have to prioritize area and habitat quality of old forest patches.     

Plastid DNA variation in highly fragmented populations of <Emphasis Type="Italic">Microbiota decussata</Emphasis> Kom. (Cupressaceae), an endemic to Sikhote Alin Mountains

Microbiota decussata Kom. (Cupressaceae) is a subalpine species endemic to the Sikhote Alin Mountains with populations scattered throughout the range. We used sequence data for four noncoding regions of chloroplast DNA to characterize the genetic diversity in populations sampled from different parts of M. decussata natural range. No variation was observed in the trnT–trnF region, whereas the trnH–psbA, trnS–trnfM, and trnS–trnG regions showed polymorphisms. At the species level, we found a low nucleotide diversity (π = 0.0009) and high haplotype diversity (h = 0.981) as well as high differentiation (Φ_ST = 0.420). N _ST and G _ST values suggested the existence of a phylogeographic structure in M. decussata. The observed patterns of diversity could be explained in part by ecological features of the species and its long-term persistence throughout the range with population expansion, successive fragmentation and isolation.     

Genetic diversity and population differentiation of traditional fonio millet (<Emphasis Type="Italic">Digitaria </Emphasis>spp.) landraces from different agro-ecological zones of West Africa

Fonio millets (Digitaria exilis Stapf, D. iburua Stapf) are valuable indigenous staple food crops in West Africa. In order to investigate the genetic diversity and population differentiation in these millets, a total of 122 accessions from five countries (Benin, Burkina Faso, Guinea, Mali and Togo) were analysed by Amplified Fragment Length Polymorphisms (AFLPs). Genetic distance-based UPGMA clustering and principal coordinate analysis revealed a clear-cut differentiation between the two species and a clustering of D. exilis accessions in three major genetic groups fitting to their geographical origins. Shannon’s diversity index detected in D. iburua was low (H = 0.02). In D. exilis, the most widespread cultivated species, moderate levels of genetic diversity (Shannon’s diversity H = 0.267; Nei’s gene diversity H′ = 0.355) were detected. This genetic diversity is unequally distributed with the essential part observed in the Upper Niger River basin while a very low diversity is present in the Atacora mountain zone. Analysis of molecular variance (AMOVA) revealed that a large part of the genetic variation resides among the genetic groups (70%) and the country of origin (56%), indicating a clear genetic differentiation within D. exilis. Influence of mating system (inbreeding or apomixis), agricultural selection and ecological adaptations as well as founding effects in the genetic make-up of the landraces were visible and seemed to jointly contribute to the genetic structure detected in this species. The genetic variability found between the analysed accessions was weakly correlated with their phenotypic attributes. However, the genetic groups identified differed significantly in their mean performance for some agro-morphologic traits. The results obtained are relevant for fonio millets breeding, conservation and management of their genetic resources in West Africa.     

<Emphasis Type="Italic">In vitro</Emphasis> and cryogenic preservation of plant biodiversity in Brazil

The Brazilian biomes (Amazon, Atlantic Forest, Cerrado, Caatinga, Pantanal, and Pampa) comprise one of the highest levels of plant diversity in the world; however, non-sustainable practices, deforestation, and land use have resulted in significant losses and fragmentation of the native forests. These ecosystems are now threatened and protection of their native plants through ex situ conservation is an urgent necessity. Cryopreservation and in vitro conservation are complementary options for securing and protecting Brazil’s native plant species because their potential economic value is critically important to develop strategies that will (1) support their sustainable utilization, (2) protect against the over-exploitation of species growing in natural habitats, and (3) conserve the genetic diversity of germplasm from species of different provenances. Biotechnological approaches will help to address future economic and environmental demands placed upon already at-risk species. Conserving seed germplasm ex situ provides an additional safeguard against the risks (e.g., loss due to disease, climate change) of field conservation. Moreover, seed banks and cryobanks permit the long-term conservation of a wider genetic base; this offsets the labor and space intensive costs of conserving in the active growing state. This paper is a compilation of the current status of strategies applied for conserving Brazilian native plant species.     

The phylogeographic structure and conservation genetics of the endangered tree peony, <Emphasis Type="Italic">Paeonia rockii</Emphasis> (Paeoniaceae), inferred from chloroplast gene sequences

The endangered species Paeonia rockii is the most important ancestral species of the cultivated tree peonies. These well-known ornamental plants are termed the ‘King of Flowers’ in China. In this study, we investigated the genetic diversity and phylogeographic structure of 335 wild samples from 20 populations throughout the entire distributional range of the species based on three chloroplast DNA sequences (petB–petD, rps16–trnQ and psbA–trnH). At those loci, high levels of genetic differentiation (G _ST  = 0.94) and low levels of genetic variation (θ = 0.00185) were detected. The intraspecific phylogeny revealed four groups, the western group, the Taibai mountain group, the northern group and the eastern group, which closely coincided with the geographic distribution of the species. A phylogeographic structure of this kind could result from a number of integrated factors, such as allopatric fragmentation, climatic fluctuations, increased abortion and declining germination of seeds, or lack of gene flow among populations, especially across the geographic barrier of the high Qinling Mountains, and it could also result from adaptive evolution. For conservation purposes, each extant population of P. rockii should be recognized as a conservation-significant unit, and a more stringent conservation strategy should incorporate in situ and ex situ methods.     

Genetic Relationship of <Emphasis Type="Italic">Curcuma</Emphasis> Species from Northeast India Using PCR-Based Markers

Molecular genetic fingerprints of nine Curcuma species from Northeast India were developed using PCR-based markers. The aim involves elucidating there intra- and inter-specific genetic diversity important for utilization, management, and conservation. Twelve random amplified polymorphic DNA (RAPD), 19 Inter simple sequence repeats (ISSRs), and four amplified fragment length polymorphism (AFLP) primers produced 266 polymorphic fragments. ISSR confirmed maximum polymorphism of 98.55% whereas RAPD and AFLP showed 93.22 and 97.27%, respectively. Marker index and polymorphic information content varied in the range of 8.64–48.1, 19.75–48.14, and 25–28 and 0.17–0.48, 0.19–0.48, and 0.25–0.29 for RAPD, ISSR, and AFLP markers, respectively. The average value of number of observed alleles, number of effective alleles, mean Nei’s gene diversity, and Shannon’s information index were 1.93–1.98, 1.37–1.62, 0.23–0.36, and 0.38–0.50, respectively, for three DNA markers used. Dendrograms based on three molecular data using unweighted pair group method with arithmetic mean (UPGMA) was congruent and classified the Curcuma species into two major clusters. Cophenetic correlation coefficient between dendrogram and original similarity matrix were significant for RAPD (r = 0.96), ISSR (r = 0.94), and AFLP (r = 0.97). Clustering was further supported by principle coordinate analysis. High genetic polymorphism documented is significant for conservation and further improvement of Curcuma species.     

Diversity Assessment of an Endemic <i>Carpinus oblongifolia</i> (Betulaceae) Using Specific-Locus Amplified Fragment Sequencing and Implications for Conservation

Carpinus oblongifolia is an endemic species and the extant wild populations show a fragmentation distribution in the Baohua Mountain of Jiangsu Province in eastern China. Understanding of genetic diversity plays an important role in C. oblongifolia survival and sustainable development. The wild C. oblongifolia population was artificially divided into four subpopulations according to the microhabitats, and another two subpopulations were constructed by progeny seedlings cultivated with the mature seeds. Then, the leaf buds of 80 individuals from six subpopulations were sampled to develop single nucleotide polymorphisms (SNPs) using specific-locus amplified fragment sequencing (SLAF-seq). Based on these SNPs, we aimed to characterize the genetic diversity and population structure of C. oblongifolia and provide an illumination and reference for effective management of such a small endemic population. The level of genetic diversity was low at the species level, and the progeny subpopulations had a relatively higher genetic diversity than the wild subpopulations. This may be attributed to a high gene flow and an excess heterozygosity to reduce the threat of genetic drift-based hazards. Moreover, the progeny subpopulations had the ability to form new clusters and a great contribution to the genetic structure variation of C. oblongifolia. These results will assist with the development of conservation and management strategies, such as properly evacuating competitive trees to provide more chance for pollen and seed flow in situ conservation, and establishing sufficient seedling plantlets under laboratory conditions for reintroduction to enlarge the effective population size.     

Feeding Ecology of <Emphasis Type="Italic">Propithecus diadema</Emphasis> in Forest Fragments and Continuous Forest

Forest fragmentation is viewed as a serious threat to primates, yet whether or not it can disrupt food resources and cause energetic stress remains largely untested. I present the results of a 12-mo study of the feeding ecology of Propithecus diadema in fragmented and continuous forest at Tsinjoarivo, eastern Madagascar. Two continuous forest groups had higher dietary diversity and ate more fleshy fruit, but during the dry season, diversity was reduced and they relied heavily on mistletoe (Bakerella clavata). In contrast, 2 groups in fragments employed the lean season strategy of eating mistletoe year-round; the fruiting tree species that sustain continuous forest groups through the rainy season were largely absent. As expected, intersite dietary overlap was highest in the dry season. The level of specialization was high: fragment groups devoted 30–40% of feeding time to Bakerella clavata, compared to 28–30% in continuous forest. The major characteristic of Bakerella clavata enabling it to be an important fallback or staple resource, or both, is its extended phenology. The difference in resource utilization between sites may have important implications for nutritional status, as well as ranging and social behavior, largely owing to the small size and high abundance of feeding patches of Bakerella. Understanding resource shifts in fragments can shed light on socioecological questions by providing comparisons between continuous forest and fragment populations with differing diets and resource distributions. In addition, understanding dietary shifts in fragments can aid in species-specific conservation efforts, while contributing to a better understanding of the considerable interspecific variability of primates in responses to fragmentation.     

Demographic bottlenecks and low gene flow in remnant populations of the critically endangered <Emphasis Type="Italic">Berchemiella wilsonii</Emphasis> var<Emphasis Type="Italic">. pubipetiolata</Emphasis> (Rhamnaceae) inferred from microsatellite markers

Berchemiella wilsonii var. pubipetiolata (Rhamnaceae) is an endangered plant with only four remnant populations in eastern China. Population genetic information is essential for understanding population history and formulating conservation strategies for this species. Thirteen microsatellite loci were used to investigate genetic variation and population structure of the four remnant populations. Moderate levels of expected heterozygosity (H _E = 0.466–0.543) and low allelic diversity (A = 3.1–3.6 and A _R = 2.2–2.4, respectively) were observed within populations. Bottleneck tests found three out of four populations to deviate from mutation-drift equilibrium under the two-phase model (TPM), suggesting a recent population decline, which is congruent with known demographic history. The evolutionary history of the species seems dominated by genetic drift rather than gene flow. Low historical gene flow was inferred from several different approaches and N _m ranged from 0.582 by the private allele method to 0.783 by the coalescent method. Contemporary gene flow was also found to be even lower for only one first generation migrant was detected with individual-based assignment analysis. Restricted pollen and seed dispersal as well as a recent decline in population size associated with habitat fragmentation may have contributed to low levels of historical and contemporary gene flow, and resulted in a high genetic differentiation. Under this scenario, Berchemiella wilsonii var. pubipetiolata populations are expected to display more pronounced population genetic structure in the future as a result of increased inbreeding and genetic drift.     

Genetic variability and structure of the remnant natural populations of <Emphasis Type="Italic">Cedrus libani</Emphasis> (Pinaceae) of Lebanon

Cedrus libani of Lebanon is a valuable natural resource and the dominant species in its natural ecosystem. Intense and diverse anthropogenic pressures over historical times raised concerns about its genetic vigor and continued survival. Our investigation of the genetic diversity included samples from all remnant natural populations. Assessment of the genetic diversity using random amplified polymorphic DNA markers revealed the persistence of considerable variation distributed within populations with low population differentiation corroborated by Bayesian and analysis of molecular variance estimates (G _ST = 0.07, Φ _ST = 0.09). Individual assignment tests were carried out to investigate measures of gene flow. Inferences concluded that this natural heritage is not currently threatened by inbreeding or by random genetic drift. Correlation studies investigated possible effects of spatial distribution and environmental conditions on genetic structure. A climatic trend corresponding to a temperature–humidity gradient correlated significantly with the level of genetic diversity, while the edaphic variation did not.     

Genetic population structure of the sagebrush Brewer’s sparrow, <Emphasis Type="Italic">Spizella breweri breweri</Emphasis>, in a fragmented landscape at the northern range periphery

Assessing the genetic consequences of habitat fragmentation is a crucial step in conservation planning for species in endangered habitats. We tested for the impact of natural habitat fragmentation on gene flow and genetic diversity in seven northern breeding locations of the sagebrush Brewer’s sparrow, Spizella breweri breweri. Genetic analyses using five highly variable DNA microsatellite loci suggested that individuals sampled within a sagebrush landscape fragmented by natural elements such as coniferous forest, comprise a single genetic population and that gene flow among them is unimpeded. We posit that juvenile dispersal links seemingly isolated breeding locales of this species, and discuss implications of our findings for conservation of migratory songbirds in the northern portion of their ranges in light of potential shifts in distribution due to climate change.     

Genetic variation and clonal structure of the rare,riparian shrub <Emphasis Type="Italic">Spiraea virginiana</Emphasis> (Rosaceae)

Genetic diversity is often considered important for species that inhabit highly disturbed environments to allow for adaptation. Many variables affect levels of genetic variation; however, the two most influential variables are population size and type of reproduction. When analyzed separately, both small population size and asexual reproduction can lead to reductions in genetic variation, although the exact nature of which can be contrasting. Genetic variables such as allelic richness, heterozygosity, inbreeding coefficient, and population differentiation have opposite predictions depending upon the trait (rarity or clonality) examined. The goal of this study was to quantify genetic variation and population differentiation in a species that resides in a highly stochastic environment and is both rare and highly clonal, Spiraea virginiana, and to determine if one trait is more influential genetically than the other. From populations sampled throughout the natural range of S. virginiana, we used microsatellite loci to estimate overall genetic variation. We also calculated clonal structure within populations, which included genotypic richness, evenness, and diversity. Gene flow was investigated by quantifying the relationship between genetic and geographic distances, and population differentiation (θ) among populations. Observed heterozygosity, genotypic richness, and inbreeding coefficients were found to be representative of high clonal reproduction (averaging 0.505, 0.1, and –0.356, respectively) and the number of alleles within populations was low (range = 2.0–3.6), being more indicative of rarity. Population differentiation (θ) among populations was high (average = 0.302) and there was no relationship between genetic and geographic distances. By examining a species that exhibits two traits that both can lead to reduced genetic variation, we may find an enhanced urgency for conservation. Accurate demographic counts of clonal species are rarely, if ever, possible and genetic exploration for every species is not feasible. Therefore, the conclusions in this study can be potentially extrapolated to other riparian, clonal shrubs that share similar biology as S. virginiana.     

Reduced MHC class II diversity in island compared to mainland populations of the black-footed rock-wallaby (<Emphasis Type="Italic">Petrogale lateralis lateralis</Emphasis>)

Many animal populations that are endangered in mainland areas exist in stable island populations, which have the potential to act as an “ark” in case of mainland population declines. Previous studies have found neutral genetic variation in such species to be up to an order of magnitude lower in island compared to mainland populations. If low genetic variation is prevalent across fitness-related loci, this would reduce the effectiveness of island populations as a source of individuals to supplement declining mainland populations or re-establish extinct mainland populations. One such species, the black-footed rock-wallaby (Petrogale lateralis lateralis), exists within fragmented mainland populations and small island populations off Western Australia. We examined sequence variation in this species within a fitness-related locus under positive selection, the MHC class II DAB β1 locus. The mainland populations displayed greater levels of allelic diversity (4–7 alleles) than the island population, despite being small and isolated, and contained at least two DAB gene copies. The island population displayed low allelic diversity (2 alleles) and fewer alleles per individual in comparison to mainland populations, and probably possesses only one DAB gene copy. The patterns of DAB diversity suggested that the island population has a markedly lower level of genetic variation than the mainland populations, in concordance with results from microsatellites (genotyped in a previous study), but preserved unique alleles which were not found in mainland populations. Where possible, conservation actions should pool individuals from multiple populations, not only island populations, for translocation programs, and focus on preventing further declines in mainland populations.     

Genetic diversity in the mtDNA control region and population structure in the small yellow croaker <Emphasis Type="Italic">Larimichthys polyactis</Emphasis>

The genetic diversity and population genetic structure of the small yellow croaker (Larimichthys polyactis) were investigated. One hundred and fourteen individuals were sampled from 8 localities of the Yellow Sea and the northern East China Sea. Genetic variation in DNA sequences were examined from the first hypervariable region (HVR-1) of the mitochondrial DNA control region. High levels of haplotype diversity (h = 0.98 ± 0.87%) in the HVR-1 region were detected, indicating a high level of genetic diverstiy. A total of 84 polymorphic sites were found, and 87 haplotypes were defined. The pairwise nucleotide differences between samples ranged from 3.83 ± 2.19 to 6.56 ± 3.25. The demographic history of L. polyactis was examined by using neutrality tests and mismatch distribution analysis, which indicated a Pleistocene population expansion at about 49,300–197,000 years. The star burst structure of the minimum spanning tree also suggestted a very recent origin for most haplotypes. Hierarchical molecular variance analysis (AMOVA) and conventional population Fst comparisons revealed no significant genetic structure throughout the examined range, which is inconsistent with previous findings based on the morphological and ecological studies. Long-term dispersal and high gene flow likely have contributed to the genetically homogeneous population structure of the species. The knowledge on genetic diversity and genetic structure will be crucial to establish appropriate fishery management stocks for the species.     

Conservation of medicinal plants of Western Ghats,India and its sustainable utilization through <Emphasis Type="Italic">in vitro</Emphasis> technology

Climate change, alien species, and use of land for intensive farming and development are causing severe threat to the plant genetic diversity worldwide. Hence, conservation of biodiversity is considered fundamental and also provides the livelihoods to millions of people worldwide. Medicinal plants play a key role in the treatment of a number of diseases, and they are only the source of medicine for majority of people in the developing world. The tropical regions of the world supply the bulk of current global demand for “natural medicine,” albeit with increasing threat to populations in the world and its genetic diversity. India is a major center of origin and diversity of crop and medicinal plants. India poses out 20,000 species of higher plants, one third of it being endemic and 500 species are categorized to have medicinal value. The Western Ghats is one of the major repositories of medicinal plants. It harbors around 4,000 species of higher plants of which 450 species are threatened. Currently, the number of species added to the red list category in this region is increasing, and the valuable genetic resources are being lost at a rapid rate. Demand for medicinal plants is increasing, and this leads to unscrupulous collection from the wild and adulteration of supplies. Providing high-quality planting material for sustainable use and thereby saving the genetic diversity of plants in the wild is important. During the last 25 years of intensive research, Tropical Botanic Garden and Research Institute has developed in vitro protocol for rapid regeneration and establishment of about 40 medicinally important rare and threatened plants of Western Ghats. In situ conservation alone would not be effective in safeguarding these important species. Thus, utilizing the biotechnoligical approach to complement ex situ conservation program is becoming vital. Propagating biotechnology tools in plant conservation program is a prerequisite to succeed in sustainable use and to complement the existing ex situ measures. In addition to propagation, storage of these valuable genetic resources is equally important. In vitro slow growth of 35 species and cryopreservation using embryo/meristem/seed in 20 different species of rare medicinal plants of this region is accomplished. Plants developed in vitro of ten medicinal plants, which have restricted distribution, were reintroduced in the natural habitat as well.     

High levels of genetic structuring as a result of population fragmentation in the tropical tree species <Emphasis Type="Italic">Caesalpinia echinata</Emphasis> Lam.

We have investigated levels of genetic diversity within and among seven remnant populations of Caesalpinia echinata Lam., an endangered species found as fragmented populations in three major areas around the coastal regions of Brazil. Using amplified fragment length polymorphism (AFLP) genetic markers, we detected levels of within-population genetic diversity ranging from 0.092 to 0.163, with the lowest values generally being found in the smallest populations. Estimates of between-population genetic differentiation were strongly correlated with geographical distance (r = 0.884, p < 0.001), which,along with a neighbour-joining phylogenetic analysis, strongly suggested high levels of genetic isolation by distance. Over half (62%) of the total genetic diversity was partitioned between populations, further highlighting the genetic distinctness of individual populations. Taken together, these results suggest that fragmentation has led to an increase in population differentiation between fragments of C. echinata. These formations will be of great value in the development of conservation plans for species exhibiting high levels of genetic differentiation due to fragmentation, such as indication of conservation unit size, which populations should be chosen as priority in conservation plans and which samples should be introduced in areas with a low number of individuals of brazilwood.     

Genetics,taxonomy and the conservation of British <Emphasis Type="Italic">Euphrasia</Emphasis>

In Britain the genus Euphrasia comprises ca 20 diploid and tetraploid plant species, including several endemics. However, their conservation is impeded by taxonomic uncertainty. Analysis of cpDNA and AFLP variation was used to assess their taxonomic status and establish the extent of barriers to gene exchange among them. Differences in ploidy level constitute a very strong barrier to genetic exchange, although this is not absolute. The diploid endemics E. vigursii and E. rivularis form morphologically and genetically definable units which show some level of reproductive isolation. Within tetraploid Euphrasia, the species showed varying degrees of distinctness. Analysis of geographically paired samples from two widespread outcrossing taxa E. arctica and E. nemorosa provides evidence for extensive genetic exchange between them. However AFLP data indicate that this outbreeding species complex possesses a gene pool distinct from that of the widespread inbreeding tetraploids. The widespread and endemic inbreeding tetraploids contain examples of morphologically and genetically definable taxa, but also species whose distinctness is more equivocal. The conservation implications of this study are that species-based action plans are potentially suitable for conservation of the diploid endemics E. vigursii and E. rivularis. In contrast we contend that a species-based conservation framework, developed with reproductively isolated and genetically distinct groups in mind, requires modification for conservation of the complex and dynamic diversity found within the tetraploids. The adoption of ‘taxonomic’ action plans, designed to protect the evolutionary processes generating Euphrasia diversity, may provide a supplementary solution for conserving this type of variation.     

Small edge populations at risk: genetic diversity of the green lizard (<Emphasis Type="Italic">Lacerta viridis viridis</Emphasis>) in Germany and implications for conservation management

Edge and central populations can show great differences regarding their genetic variation and thereby also in their probability of extinction. This fact might be of great importance for the conservation strategies of endangered species. In this study we examine the level of microsatellite variability within three threatened edge populations of the green lizard subspecies Lacerta viridis viridis (Laur.) in Brandenburg (Germany) and compare the observed variation to other edge and central populations within the northern species range. We demonstrate that the northernmost edge populations contain less genetic variation in comparison to the central population. However, there were no observable significant differences to the other edge population included in this study. Surprisingly, we observed a high genetic differentiation in a small geographical range between the three endangered populations in Brandenburg, which can be explained by processes like fragmentation, isolation, genetic drift and small individual numbers within these populations. We also detected unique genetic variants (alleles), which only occurred in these populations, despite a low overall genetic variation. This study demonstrates the potential of fast evolving markers assessing the genetic status of endangered populations with a high resolution. It also illustrates the need for a comparative analysis of different regions within the species range, achieving a more exact interpretation of the genetic variation in endangered populations. This will aid future management decisions in the conservation of genetic diversity in threatened species.     

Genetic variation and phylogenetic relationship between two species of yellow catfish, <Emphasis Type="Italic">Horabagrus brachysoma</Emphasis> and <Emphasis Type="Italic">H. nigricollaris</Emphasis> (Teleostei: Horabagridae) based on RAPD and microsatellite markers

The two species of yellow catfish, Horabagrus brachysoma and H. nigricollaris are categorized as ‘endangered’ and ‘critically endangered’ respectively in their wild habitat. Proper knowledge of genetic structure and variability of these endangered species are highly essential for the management, conservation and improvement of fish stocks. Therefore, genetic variation and phylogenetic relationships between these species of yellow catfish sampled from Chalakkudy River in the hot spot of biodiversity-Western Ghats region, Kerala, India were analyzed by using Random amplified polymorphic DNA (RAPD) and microsatellite markers. 85 RAPD and five microsatellites loci were detected to analyze the genetic variation and phylogenetic relationships among these species. Out of 85 RAPD loci produced only 52.94% were polymorphic whereas in microsatellite, all 5 loci were polymorphic (100%). Species-specific RAPD bands were found in both species studied. In microsatellite, the number of alleles across the five loci ranged from 1 to 8. The observed heterozygosities in H. brachysoma and H. nigricollaris were 0.463 and 0.443, respectively. Here, both RAPD and microsatellite methods reported a low degree of gene diversity and lack of genetic heterogeneity in both species of Horabagrus which strongly emphasize the need of fishery management, conservation and rehabilitation of these species.