Allozymic variation and relationships of the endangered cyprinodontid genus Valencia and its implications for conservation

Allozyme analysis was used to determine patterns of genetic variation and relationships within the genus Valencia , a group with two allopatric species, V. letourneuxi inhabiting the Balkan Peninsula, and V. hispanica which is endemic to the Iberian Peninsula. Products of 25 gene loci were analysed with AK *, FH *, LDH -1* and LDH -2* monomorphic when Fundulus heteroclitus macrolepidotus was not taken into account. Nine loci were diagnostic for both species of the genus Valencia . Levels of genetic variation of V. hispanica ( P =0·416, H ^e=0·118) and V. letourneuxi ( P =0·160, H _e=0·040) were higher than values reported previously. High population subdivision ( F _st=0·321) among V. hispanica populations indicates a clear interruption of genetic exchange among populations. High genetic variation and differentiation exhibited by populations of V. hispanica suggest that a recovery program should be carried out with natural stocks from the same localities.     

Desert fishes: an interdisciplinary approach to endangered species conservation in North America

The habitat degradation and species endangerment that preceded and accompanied the North American environmental movement in the late 1960s and early 1970s found the conservation community ill-prepared. Protective legislation and basic research necessary for structuring recovery efforts did not exist. Desert aquatic communities were among the first to need attention, and an interdisciplinary effort was mounted in an early application of conservation biology. The history and evolution of desert ecosystem preservation are discussed, and case histories are presented that may prove helpful in other parts of the world as habitats are inexorably reduced. The role of the Desert Fishes Council in co-ordinating efforts of research scientists and resource managers to achieve common objectives is emphasized.     

濒危物种巴东木莲的等位酶遗传多样性及其保护策略

为了确定中国特有濒危植物巴东木莲(Manglietia patungensis)的就地保护优先单元和制定迁地保护的取样策略,采用超薄平板聚丙烯酰胺等电聚焦电泳技术对巴东木莲的7个野生居群的等位酶遗传多样性及遗传结构进行了分析。通过对8个酶系统19个酶位点的分析结果来看,巴东木莲具有较高的遗传多样性和一定程度的遗传分化。每位点平均等位基因数（A）为1.57,多态位点百分率（P）为48.1%,平均预期杂合度（H_e）为0.192。巴东木莲居群间的遗传分化系数（G_ST）为0.165,说明其16.5％的遗传变异存在于居群间;基于遗传分化系数计算的基因流（N_m）为1.27,说明居群间存在适度的基因流;固定指数(F)为-0.191,显示巴东木莲居群杂合体轻微过量,纯合体略显不足。本研究表明,目前巴东木莲仍具有较高的遗传多样性并且在其适宜生境中可以完成自然更新,因此应采取以就地保护为主的综合保育策略。     

Phylogenetic relationship,biogeography, and conservation genetics of endangered Fraxinus chiisanensis (Oleaceae), endemic to South Korea

Endemic plants are important for understanding phylogenetic relationships, biogeographical history, and genetic variation because of their restricted distribution and their role in conserving biodiversity. Here, we investigated the phylogenetic relationships of the Korean endemic Fraxinus chiisanensis by reconstructing the molecular phylogeny of Fraxinus based on two nuclear DNA (nrITS and phantastica) and two chloroplast DNA (psbA-trnH and rpl32-trnL) regions. Within our fossil-calibrated phylogenetic framework, we also inferred the biogeographical history of F. chiisanensis. To provide a scientific basis for the conservation of F. chiisanensis, we determined the levels of genetic diversity and genetic differentiation in this species. Combining information from nuclear and chloroplast DNA sequence data, our molecular phylogenetic analyses identified F. chiisanensis as a genetically distinct unit from its sister group, Fraxinus platypoda from Japan. Our molecular dating analyses using nuclear and chloroplast DNA data sets show F. chiisanensis diverged from its sister F. platypoda in the Early or Middle Miocene and differentiated in the Late Miocene on the Korean Peninsula. Our results suggest that the divergence of F. chiisanensis was associated with the submergence of the East China Sea land bridge and enhanced monsoons in East Asia. When compared to F. platypoda, F. chiisanensis exhibits low genetic diversity within populations and high genetic differentiation among populations. These results help us to understand the evolutionary history of F. chiisanensis and to develop a conservation strategy for this species.     

Allozyme variation of the endangered endemic plant Myricaria laxiflora: Implications for conservation

Myricaria laxiflora, a riparian plant that naturally occurs in the riverbanks of the Yangtze River Valley, has become extinct across its entire geographical distribution range in the wild due to the construction of the Three Gorges Dam. The allozyme variation of M. laxiflora populations was investigated in the present study. Mean number of alleles per locus (A) was 2.35, and the observed heterozygosity (H_o) and expected heterozygosity (H_e) were 0.35 and 0.30, respectively. Six populations showed significant excesses of heterozygotes based on the examination of a multilocus fixation index (F_IS). The population genetic divergence of M. laxiflora is high (G_ST = 0.144 and ?_B = 0.131) and the analysis of molecular variance analysis shows that 19.71% of the total genetic variation is caused by the difference between populations. Based on the obtained genetic information, six management units have been identified, all of which are expected to enhance the effective management of the remaining and transplanted individuals of this endangered species in the future.     

濒危兰科植物再引入技术及其应用

稀有、濒危植物的再引入,是在条件成熟时,把经过迁地保护的人工繁殖体重新放回到它们原来自然和半自然的生态系统或适合它们生存的野外环境中去,重建较为完善的生态系统。再引入技术的目标在于提高生态系统生物多样性及群落稳定性,建立可自我维持种群,它是继就地保护和迁地保护等保护策略之外的一种新兴的珍稀濒危植物保育方式。国际上再引入技术的研究刚起步,高度成功的还不多,目前可借鉴的成熟经验较少。通过分析国内外已经开展的若干珍稀濒危植物再引入技术案例,重点介绍国内外濒危兰科植物再引入的研究现状、技术体系和评价标准,讨论了再引入技术的类型和方法,并总结了可能影响再引入成败的制约性因素,分析了适用于兰科植物的再引入技术要素。由此提出濒危兰科植物再引入的重要现实意义,为今后的规模化人工栽培提供科学依据,同时有利于指导其他濒危植物再引入技术规程的制定。     

Genetic variation in populations of the endangered fish Ladigesocypris ghigii and its implications for conservation

1. The genetic variation of the endangered freshwater fish Ladigesocypris ghigii, endemic to the island of Rhodes (Greece), was investigated for nine populations, originating from seven different stream systems and a reservoir, both at the mtDNA and nuclear level, in order to suggest conservation actions. 2. Both restriction fragment length polymorphism analysis of five segments of mitochondrial DNA (ND‐5/6, COI and 12S‐16S rRNA) amplified by polymerase chain reaction, and random amplified polymorphic DNA analysis, revealed extremely low levels of intra‐population polymorphism. It is highly likely that the low intra‐population variability is the result of successive bottleneck events evident in shrinkage and expansion of the populations year after year, which may have led to a complete loss of several genotypes and haplotypes, and an increased degree of inbreeding. 3. Inter‐population genetic structuring was high, with fixation of haplotypes within six of the nine populations and fixation of alleles within populations originating from different waterbodies. It is probable that all haplotypes and/or alleles found were initially represented in all populations. However, because of the long time of isolation coupled with successive bottleneck and subsequent genetic drift, common mtDNA haplotypes and alleles among the populations may have become rare or extinct through stochastic lineage loss. 4. Although nucleotide divergence among haplotypes was very shallow, half of the haplotypes recorded (three of six), resulted from nucleotide changes on the 12S–16S rRNA segments, which are the most conserved part of the mitochondrial genome. This fact may indicate that the observed genetic variation did not necessarily result only from the retention of ancestral polymorphism, but may have arisen through mutation and complete lineage sorting over a relatively small number of generations, once the populations had become isolated from one another. 5. Our data suggest that two of the L. ghigii populations may be on independent evolutionary trajectories. Considering that each population appears so far well adapted within each site, all populations should be managed and conserved separately.     

Low genetic diversity and significant structuring in the endangered Mentha cervina populations and its implications for conservation

Eighteen populations of the endangered aromatic and medicinal plant Mentha cervina (Lamiaceae) were sampled across its natural range, in the western half of the Iberian Peninsula, and inter-simple sequence repeats (ISSRs) markers were used to assess genetic diversity and population structure. M. cervina populations exhibited a relatively low genetic diversity (percentage of polymorphic loci PPB = 14.2–58.3%, Nei's genetic diversity H_e = 0.135–0.205, Shannon's information index I = 0.08 − 0.33). However, the genetic diversity at species level was relatively high (PPB = 98.3%; H_e = 0.325; I = 0.23). The results of the analysis of molecular variance indicated very structured populations, with 50% of the variance within populations, 44% among populations and 6% between regions defined by hydrographic basins, in line with the gene differentiation coefficient (G_ST = 0.532). A Mantel test did not find significant correlation between genetic and geographic distance matrices (r = 0.064), indicating that isolation by distance is not shaping the present genetic structure. The levels and patterns of genetic diversity in M. cervina populations were assumed to result largely from a combination of evolutionary history and its unique biological traits, such as breeding system, low capacity of dispersion, small effective size and habitat fragmentation. The high genetic differentiation among populations indicates the necessity of conserving the maximum possible number of populations. The results also provide information to select sites for ex situ conservation. Optimal harvesting strategies, cultivation and tissue culture should also be developed as soon as possible to guarantee sustainable use of the species under study.     

Genetic structure of endangered Emmenopterys henryi Oliv. based on ISSR polymorphism and implications for its conservation

Inter-simple sequence repeat (ISSR) markers were used to determine the genetic variation and genetic differentiation of nine populations of Emmenopterys henryi Oliv., an endangered plant endemic to China. Relatively low genetic diversity was detected at population level (the percentage of polymorphic loci P=22.56%, the number of alleles per locus A=1.183+/-0.045, the effective number of alleles per locus A(E)=1.007+/-0.345, Nei's gene diversity h=0.071+/-0.017, Shannon information index I=0.104+/-0.025). However, the genetic diversity at species level was relatively high (P=56.05%; A=1.561+/-0.498, A(E)=1.325+/-0.371, h=0.191+/-0.199, I=0.287+/-0.284). Analysis of molecular variance showed that most of the ISSR variation (68.03%) in E. henryi occurred among populations. The estimated Nm from F (ST )was 0.235. It indicated that the fragmentation and isolation of populations might result from specific evolutionary history and anthropogenic activity. Consequently, genetic drift might play an important role in determining the genetic structure of E. henryi. Conservation strategies for this endangered species are proposed based on the genetic data.     

Genetic variability inCebus appella paraguayanus: Biochemical analysis of seven loci and variation in Glyoxalase I (E.C.4.4.1.5)

An analysis of seven loci inCebus apella paraguayanus showed that Glyoxalase I was polymorphic due the appearance of two alleles (GLO*2 andGLO*3) with frequencies of 0.955 and 0.045, respectively. Of the two alleles,GLO*2 was electrophoretically similar to the most common allele found in the human andAotus. These results confirmed our previous findings in the same population sample showing that this subspecies has a very low genetic variation among New World primates.     

Genetic characterization of Gainj- and Kalam-speaking peoples of Papua New Guinea

The research presented focuses on genetic variation in the Gainj- and Kalam-speaking peoples of highland Papua New Guinea. The primary data are typings at 51 genetic loci observed on 600 individuals who reside in 21 census units, called parishes. These data are augmented by cultural and demographic information that has also been collected. Parish sizes are small, ranging from 20 to about 200 individuals. Direct Western contact with these people has been occurring only for the past three decades. Although Westernization is currently increasing, we find that much of the traditional settlement pattern and mate exchange system is preserved. There are segregating variants at 27 loci. Four rare variants are initially described: NP 4-Kalam, ADA 6-Kalam, PEPA 3-Kalam, and FUM 2-Kalam. We find evidence for a new Gm haplotype, a;-, that is recessive to all other Gm haplotypes. It occurs at a high enough frequency, f(a;-) = 0.119, to be considered a "private polymorphism." Average per locus heterozygosity is estimated to be 0.053. This value is not statistically different from levels observed on two modern urban populations. Thus, there is no evidence for a reduced level of genetic variation in these people, despite small parish sizes and a relatively unacculturated social structure.     

Genetic variation and conservation of Changnienia amoena, an endangered orchid endemic to China

Nuclear DNA content (2C) is used as a new criterion to investigate nearly all species of the genus Nerine Herb. The species have the same chromosome number (2n = 2x = 22), with the exception of three triploid plants found. The nuclear DNA content of the diploids, as measured by flow cytometry with propidium iodide, is demonstrated to range from 18.0–35.3 pg. This implies that the largest genome contains roughly 2 × 10¹⁰ more base pairs than the smallest. The species, arranged according to increasing genome size, fell apart in three groups if growth cycle and leaf width were also considered. A narrow-leafed, evergreen group with a DNA content between 18.0 and 24.6 pg contains thirteen species, a broad-leaved winter growing group with four species has a DNA content from 25.3–26.2 pg and a broad-leafed summer growing group has a DNA content of 26.8–35.3 pg and contains six species. If the presence of filament appendages and hairiness of the pedicels were also considered, the thirteen evergreen species could be further divided into a group without filament appendages or hairy pedicels with a DNA content of 18.0–18.7 pg. A second group without filament appendages but with hairy pedicels had a DNA content of 19.7–22.3 pg. And a third group with both filament appendages and hairy pedicels had a DNA content of 22.0–24.6 pg. The exception is N. marincowitzii that, despite a low DNA content and narrow leaves is summer growing. The broad-leafed group is further characterised by the absence of filament appendages and the absence of strongly hairy pedicels. The exception here is N. pusilla that, despite a high DNA content, has narrow leaves and minutely hairy pedicels. Nuclear DNA content as measured by flow cytometry is shown to be relevant to throw new light on the relationships between Nerine species.     

Mate choice evolution, dominance effects, and the maintenance of genetic variation

Female mate choice influences the maintenance of genetic variation by altering the mating success of males with different genotypes. The evolution of preferences themselves, on the other hand, depends on genetic variation present in the population. Few models have tracked this feedback between a choice gene and its effects on genetic variation, in particular when genes that determine offspring viability and attractiveness have dominance effects. Here we build a population genetic model that allows comparing the evolution of various choice rules in a single framework. We first consider preferences for good genes and show that focused preferences for homozygotes evolve more easily than broad preferences, which allow heterozygous males high mating success too. This occurs despite better maintenance of genetic diversity in the latter scenario, and we discuss why empirical findings of superior mating success of heterozygous males consequently do not immediately lead to a better understanding of the lek paradox. Our results thus suggest that the mechanisms that help maintain genetic diversity also have a flipside of making female choice an inaccurate means of producing the desired kind of offspring. We then consider preferences for heterozygosity per se, and show that these evolve only under very special conditions. Choice for compatible genotypes can evolve but its selective advantage diminishes quickly due to frequency-dependent selection. Finally, we show that our model reproduces earlier results on selfing, when the female choice strategy produces assortative mating. Overall, our model indicates that various forms of heterozygote-favouring (or variable) female choice pose a problem for the theory of sexual ornamentation based on indirect benefits, rather than a solution.     

High regional genetic differentiation of an endangered relict plant Craigia yunnanensis and implications for its conservation

Of the genus Craigia, widespread in the Tertiary, only two relict species survived to modern times. One species is now possibly extinct and the other one, Craigia yunnanensis, is severely endangered. Extensive surveys have located six C. yunnanensis populations in Yunnan province, southwest China. Using fluorescent amplified fragment length polymorphism (AFLP), the genetic diversity and population structure of these populations were examined. It was found that genetic diversity of C. yunnanensis was moderate at the species level, but low at regional and population levels. Analysis of population structure showed significant genetic differentiation between Wenshan and Dehong regions, apparently representing two geographically isolated for long time refuges. There are also clear indications of isolation between populations, which, together with anthropogenically caused decline of population size, will lead to general loss of the species genetic variation with subsequent loss of adaptive potential. To conserve the genetic integrity of C. yunnanensis, we recommend that ex-situ conservation should include representative samples from every population of the two differentiated regions (e.g. Wenshan and Dehong). The crosses between individuals originated from different regions should be avoided because of a high risk of outbreeding depression. As all the extant populations of C. yunnanensis are in unprotected areas with strong anthropogenic impact, there is no alternative to reintroduction of C. yunnanensis into suitable protected locations.     

Genetic diversity of the endangered Chinese endemic herb Saruma henryi Oliv. (Aristolochiaceae) and its implications for conservation

Saruma henryi Oliv., the only representative of the monotypic genus Saruma Oliv. (Aristolochiaceae), is an endangered perennial herb endemic to China. It is a phylogenetically, ecologically, and medicinally important species. In the present study, inter-simple sequence repeat (ISSR) markers were employed to investigate the genetic diversity and differentiation of 14 populations. A total of 16 selected primers yielded 175 bright and discernible bands, with an average of 10.94 per primer. POPGENE analysis showed that the genetic diversity was quite low at the population level (h = 0.0447–0.1243; I = 0.0642–0.1853; PPB = 10.29–36.57%), but pretty high at the species level (h = 0.2603; I = 0.3857; PPB = 73.71%). The hierarchical analysis of molecular variance (AMOVA) revealed a high level of genetic differentiation among populations (67.18% of total variance components, P < 0.001), in line with the gene differentiation coefficient (G _ST = 0.6903) and the limited among-population gene flow (N _m = 0.2243). Both Principal Coordinates Analysis (PCoA) and UPGMA cluster analysis supported the grouping of all 14 populations into three geographic groups, among which there occurred a moderate level of genetic differentiation (33.18% of total variance components, P < 0.001) as shown by AMOVA analysis. In addition, Mantel test revealed a significant correlation between genetic and geographic distances among populations (r = 0.7792, P = 0.001), indicating the role of geographic isolation in shaping its present population genetic structure. The present levels and patterns of genetic diversity of S. henryi were assumed to result largely from its breeding system, geographic isolation, clonal growth, its unique biological traits and evolutionary history. The high genetic differentiation among populations implies that the conservation efforts should aim to preserve all the extant populations of this endangered herb.     

Biotechnological approaches for conservation and improvement of rare and endangered plants of Saudi Arabia

Genetic variation is believed to be a prerequisite for the short-and long-term survival of the plant species in their natural habitat. It depends on many environmental factors which determine the number of alleles on various loci in the genome. Therefore, it is important to understand the genetic composition and structure of the rare and endangered plant species from their natural habitat to develop successful management strategies for their conservation. However, rare and endangered plant species have low genetic diversity due to which their survival rate is decreasing in the wilds. The evaluation of genetic diversity of such species is very important for their conservation and gene manipulation. However, plant species can be conserved by in situ and in vitro methods and each has advantages and disadvantages. DNA banking can be considered as a means of complimentary method for the conservation of plant species by preserving their genomic DNA at low temperatures. Such approach of preservation of biological information provides opportunity for researchers to search novel genes and its products. Therefore, in this review we are describing some potential biotechnological approaches for the conservation and further manipulation of these rare and endangered plant species to enhance their yield and quality traits.     

Population structure of Alaskan and Siberian indigenous communities

Genetic data consisting of 14 red cell antigen groups and 11 serum and erythrocytic protein marker systems from four Eskimo populations of the Norton Sound area of Alaska are reported. The population structure of these four groups is analyzed both separately and within the larger context by comparison to 15 other circumpolar groups. These analyses reveal a good fit between genetic structure, geographic distribution, linguistic affiliation, and the ethnohistory of the region.