Analysis of genetic variation in unisexual and bisexual lizard species of the genus Leiolepis from Southeast Asia

Using multilocus DNA fingerprinting with microsatellite probes (CAC)5, (GACA)4, (GGCA)4 and (GATA)4, intraspecific variation of the Southeast Asian lizards belonging to the genus Leiolepis (bisexual species Leiolepis reevesii and triploid parthenogenetic species Leiolepis guentherpetersi) was first examined. The L. guentherpetersi lizards were characterized by monophyletic DNA fingerprint profiles for the loci detected by the (GACA)4, (GGCA)4, and (CAC)5 probes, in terms of intrapopulation similarity index constituting S = 0.96. This was different from the individual-specific profiles of the lizards from bisexual, presumably parental species, L. reevesii (S = 0.6; P < 0.001). Genetic homogeneity of triploid L. guentherpetersi lizards at the loci examined serves as one of the arguments for the parthenogenetic nature of this species. Genetic variability of triploid parthenogenetic species L. guentherpetersi appeared to be comparable with that reported earlier for the Caucasian rock lizards of the genus Darevskia, namely, D. dahlia, D. armeniaca, and D. unisexualis (P > 0.05). The results of DNA fingerprinting analysis of the same L. guentherpetersi samples with the (GATA)4 hybridization probe were unexpected. Variability of parthenogenetic species L. guentherpetersi at the (GATA)n markers was remarkably higher than that at other DNA markers (S = 0.35; P = 3.08 x 10(-11)), being comparable to the variation of the (GATA)n DNA markers in bisexual species L. reevesii (P = 0.74). The reasons for high polymorphism of the (GATA)n-containing loci in L. guentherpetersi still remain unclear. This polymorhism is probably associated with high instability of the loci, which can be revealed by means of family analysis of parthenogenetic offspring.     

Low genetic variation detected within the widespread mangrove species Nypa fruticans (Palmae) from Southeast Asia

Genetic diversity within and among six natural populations of Nypa fruticans from China, Vietnam, and Thailand was assessed using SSR and ISSR analysis. Our results showed an extremely low level of genetic diversity of N. fruticans (at the species level, P = 11.76% and 2.88%, He = 0.0279 and 0.0113, I = 0.0470 and 0.0167 by SSRs and ISSRs, respectively) across a total of 183 individuals. No genetic variation was detected within any population except for the Thailand population by SSRs (P = 11.76%, He = 0.0417; I = 0.0622). The bottlenecks during glacial epochs, founder effects, and propagation pattern may be responsible for the extremely low level of genetic diversity of N. fruticans.     

Finding of Bov-B LINE retroelement in parthenogenetic and bisexual lizard species of the genus Darevskia (Lacertidae)

The Bov-B LINE retrotransposon was first discovered in Ruminantia and was long considered to be specific for this order. Later, this mobile element was described in snakes and some lizard species. Analysis of phylogenetic relationships of Bov-B LINE elements from different ruminants, snakes, and lizard species led to the suggestion on horizontal transfer of this retrotransposon from Squamata to Ruminantia. In the Squamata group, Bov-B LINE element was found in all snakes and some lizard species examined. The element was not detected in the genomes of some species of the genera Lacerta and Podarcis. In the present study, using PCR amplification and sequencing of PCR products, Bov-B LINE element was identified in the genomes of parthenogenetic and bisexual species of the genus Darevskia (Lacertidae), as well as in such species as Lacerta agilis and Zootoca vivipara, where this retrotransposon had not been not detected before.     

Karyotypic variation in bisexual species and pseudogamous forms of the planthopper genus Ribautodelphax (Homoptera,Delphacidae)

Chromosome numbers of Ribautodelphax collinus. R. angulosus, R. pungens, R. imitans, R. fanari, R. pallens, R. albostriatus, and of four undescribed species, provisionally indicated as Taxon 1 to 4, were determined. The chromosome number of all species was found to be 2n=30 (14II+XX-XO); however, in several species some females with 2n=31 or 32 also occurred. One female of R. collinus and one of Taxon 1 possessed eggs with 16 bivalents and one egg with 32 bivalents. One female of R. pungens contained only tetraploid eggs. Pseudogamous triploid females occurred in populations of R. pungens and Taxon 4. Their chromosome numbers ranged from 3n=40 to 46 in R. pungens and 3n=41 to 45 in Taxon 4. In several pseudogamous females from two R. pungens populations, eggs with 45 univalents and with various numbers of univalents, bivalents and trivalents were found. The mode of origin of pseudogamous triploid females is discussed and it is concluded that karyotypic data are consistent with an autopolyploid origin.     

Cytological evidence for temporal differences during the asynchronous ovarian maturation of bisexual and unisexual fishes of the genus Poecilia

Comparisons based upon morphological features and cytochemical staining properties of chromatin, nucleoli, and the ooplasm were used in the present analysis of ovarian maturation in wild-caught Poecilia mexicana and its related gynogenetic diploid and triploid' species'. Using an empirically derived ovarian maturation index, seasonal and collection site differences were found between the unisexual and bisexual forms. These fish seem equally suited to their environments. However, our data indicate that differences in microhabitat can have a profound influence on oocyte development. Although females of Poecilia spp. have asynchronous cycles of ovarian maturation, we could not detect any peculiar cytological events associated with the gynogenetic mode of reproduction. Sperm were found in ovaries of both unisexual and bisexual forms indicating that the unisexuals can compete effectively with females of P. mexicana for matings with males of this species. The methods employed in this study provide a sensitive measure of reproductive potentials in sympatric species.     

东南亚青年人群中马拉色菌菌种构成分析

目的：研究部分东南亚国家青年人群中马拉色菌菌种构成。方法采集285名青年人（分别来源于中国、尼泊尔、印度、巴基斯坦）面部正常皮肤及皮损区标本,接种于 Leeming ＆amp; Notman 培养基后进行培养分离,生化及形态学方法鉴定到种。结果共分离出8个菌种,共计501株马拉色菌,以球形马拉色菌为主,占40.5℅（203/501）,其次为合轴马拉色菌19.0℅（95/501）、糠秕马拉色菌16.0℅（80/501）、限制马拉色菌11.0℅（55/501）、斯洛菲马拉色菌6.2℅（31/501）等。各国家间未见明显的地理学差异。结论东南亚地区青年正常人群及马拉色菌相关疾病患者中的主要菌种为球形马拉色菌。     

A new genus and species of proteocephalidean tapeworm (Cestoda) from Pangasius larnaudii (Siluriformes: Pangasiidae) in Southeast Asia

A new proteocephalidean cestode is described from spot pangasius, Pangasius larnaudii (Siluriformes: Pangasiidae), from Tonle Sap Lake in Cambodia and a new genus, Pangasiocestus , is proposed to accommodate it. The genus is placed in the Gangesiinae because its scolex possesses a large rostellum-like apical organ and its genital organs (testes, ovary, vitellarium, and uterus) are situated in the medulla, with some vitelline follicles paramuscular. Pangasiocestus romani n. gen. and n. sp., the type and only species of the new genus, is characterized mainly by its rosette-like scolex composed of 4 lobes bearing a small sucker in their center, and the apical part with a large, discoidal, rostellum-like apical organ devoid of hooks, by weakly developed inner longitudinal musculature formed by very few isolated muscle fibers, uneven size of testes in immature and mature proglottids, with lateral testes smaller and more dense than median ones, by very narrow lateral bands of vitelline follicles, formed usually by single follicles, and by the vagina anterior to the cirrus sac. This is the first proteocephalidean cestode from a pangasiid catfish identified to the species level (proteocephalidean cestodes from 3 Pangasius spp. reported in an unpublished account from Vietnam, misidentified as Proteocephalus osculatus (Goeze, 1782) [?= Glanitaenia osculata ], are not considered).     

Sporophyte formation in experimentally-induced unisexual female and bisexual gametophytes ofLygodium japonicum

Unisexual female and male and bisexual gametophytes were experimentally induced inLygodium japonicum. A single bisexual gametophyte was isolated in a dish and a female gametophyte was paired with a male one to allow intragametophytic selfing and intergametophytic mating, respectively. About 30% of the females formed sporophytes but no bisexual gametophytes formed them.     

Reduction of competition between bisexual and unisexual females ofPoecilia in northeastern Mexico

Synopsis Breeding compexes of poeciliid fishes with a bisexual and two unisexual species were studied for mechanisms permitting Sympatric coexistence. The unisexuals are gynogenetic and thereby sexually dependent on the males of the bisexual species for sperm to initiate development, but inheritance is entirely maternal.Bisexual females are more abundant in headwater localities; unisexuals increase in downstream localities. Males were 10 – 18% of the total poeciliid population, regardless of the relative proportions of bisexual to unisexual females. Downstream localities were typified by greater habitat diversity, including a variety of backwater pools. The unisexuals showed a marked preference for such pools. Both field and laboratory studies showed that all three types of females as well as males preferred shaded areas with a gravel substrate.Although the four types of fish were found together, nearest neighbour data indicated that each type of female preferred its own kind. Males courted throughout the year and were indiscriminate in their choice of mates. Despite the skewed sex ratio, males were not in short supply because only a few females were sexually receptive at a given time. No significant differences existed between bisexuals and unisexuals in their relative reproductive outputs, but they were asynchronous.     

Invasive species in Southeast Asia: the knowledge so far

This review deals with alien species invasion in Southeast Asia, an important conservation and management concern in the region. I report on the current and potential future impacts of biological invasions on biodiversity in Southeast Asia. Current knowledge of the invasive species in Southeast Asia is mostly based on anecdotal observations. Nevertheless, I attempt to compile existing empirical evidence on the negative effects of the biological invaders found in the region. These impacts include displacement of native biota, modification of ecosystems, hybridization, environmental disturbance, and economic loss. Any effective counter-measure will need to involve a multi-national strategy, yet such measure is challenging due to a broad spectrum of political and economic development models among the Southeast Asian countries. An overview of the taxonomic structure of the invasive species in Southeast Asia shows that the invasive plant and fish are the most represented taxonomic groups in all countries. The current research effort in invasion ecology from Southeast Asia is not being up to international standard in comparison to other regions, and the absence of recent international journal articles on invasive plant species reveals the biases in biological invasion-related research. The lack of research capacity and financial support from governments, and the inability to disseminate scholarly data in international journals are the possible reasons for the dearth of research literature on biological invasions from the region. Finally, a forward-looking agenda for the region should include improving the quality and quantity of biological invasion research; adopting a tough approach to the illegal release of wildlife; and applying multi-national strategies that integrate data sharing, prioritization, public awareness, policy work, capacity building, conservation actions and surveillance.     

Correlates of sprinting, jumping and parachuting performance in the butterfly lizard, Leiolepis belliani

Leiolepis belliani , a cursorial, beach-dwelling lizard, moves by running and jumping. The lizards' ability to flatten dorsoventrally, thereby increasing surface area and decreasing wing loading, may also confer parachuting ability. We measured locomotor performance of three ecologically relevant tasks: running, jumping and parachuting. In addition, we investigated whether, with the effect of size removed, locomotor performance capabilities are correlated, and whether they correlate with morphological features. Larger lizards fell and ran faster and jumped further. Lizards that were experimentally prevented from flattening fell faster than control lizards. When the effects of size were removed, limb length was uncorrelated with jumping and running performance; performance measures also were not correlated amongst themselves. The scant natural historical data available for this species suggests that lizards do not use their parachuting capability, and that dorsoventral flattening may have evolved for some other purpose. Leiolepis might serve as a useful model in understanding the evolution of gliding lizards (e.g. Draco ).     

Genome size variation and species relationships in the genus Hydrangea

Genome size and base composition in 16 species and subspecies of the Hydrangea, a woody ornamental genus of Hydrangeaceae, were evaluated by flow cytometry in relation to their chromosome number. This is the first such study concerning the genome size of these species together with a karyotype study of the most important species, Hydrangea macrophylla subsp. macrophylla (Hortensia), from an economical point of view. The 2C DNA content ranged from 1.95 pg in Hydrangea quercifolia to 5.00 pg in Hydrangea involucrata. The base composition ranged from 39.9% GC in Hydrangea aspera subsp. sargentiana to 41.1% in Hydrangea scandens subsp. scandens (significant difference at p < 0.05). The smallest genome sizes were those of the three species originating from North or South America. Most of the species studied presented a chromosome number of 2n = 2x = 36, except for those of the section Aspereae which showed 2n = 30, 34 and 36. A primary karyotype has been made for the first time for H. macrophylla subsp. macrophylla. Phylogenetic relationships between species, the origin of chromosome number and an exploration of the genetic diversity within the genus are discussed. Received: 24 July 2000 / Accepted: 31 October 2000     

New species of the Inoceramus-like bivalve genus Maitaia Marwick from the Permian of northeastern Asia

Historical development of Permian Inoceramus-like bivalves of the bipolar genus Maitaia Marwick in northeastern Asia is briefly considered. Five new species (Maitaia vedernikovi sp. nov., M. kusnezovi sp. nov., M. orulganica sp. nov., M. regularicostatum sp. nov., and M. tobonnoensis sp. nov.) from the Middle and Upper Permian of the Omolon Massif, northern, western, and southern Verkhoyansk Region are described.     

Natural genetic variation in MIR172 isolated from Brassica species

The present study reports a natural variation in microRNA172 (MIR172) family members isolated from six species of genus Brassica. The analysis of nucleotide polymorphism across 44 Brassica MIR172 homologs revealed a higher conservation in the predicted precursors relative to flanking regions. Single nucleotide polymorphisms (SNPs) were detected in miRNA and miRNA*. The 21-nt miRNA sequence was conserved in all MIR172 members except MIR172a. However, the miRNA* sequence was conserved only in MIR172a compared to A. thaliana. Non-canonical Brassica variants of precursor miR172a were detected wherein SNP at 5′ terminal in mature miR172a resulted in a sequence identical to mature miR172e. SNPs and indels in precursors resulted in varied stem-loop structures of differing stabilities (ΔG) implying a differential efficiency of miRNA biogenesis. A sequence based phylogram revealed ortholog specific groupings of MIR172 irrespective of genetic background. A Northern analysis in Brassica juncea displayed the cumulative expression of miR172 isoforms in all tissues representing different developmental stages with levels gradually increasing from vegetative to reproductive stages. Detection of high content of miR172 in roots indicates the possibility of additional roles of Brassica miR172 in root development.     

A remarkable new genus of leafhoppers (Hemiptera,Cicadellidae, Iassinae) from Southeast Asia

Tardrabassus pakneunensis, n. gen. & sp. is described and illustrated. The new genus shows morphological affinities to three leafhopper subfamilies, Tartessinae, Deltocephalinae, and Iassinae, but is tentatively placed in Iassinae based on the position of the ocelli, the reduced lateral frontal sutures, the leg chaetotaxy, and the structure of the male genitalia.     

Origin of the unisexual lizard Gymnophthalmus underwoodi (Gymnophthalmidae) inferred from mitochondrial DNA nucleotide sequences

Analysis of variation in nucleotide sequences in mitochondrial DNA genes among species of Gymnophthalmus supports three major conclusions. First, samples of G. underwoodi, a unisexual species of hybrid origin, have identical nucleotide sequences, supporting the hypothesis that all individuals from localities in the Guianan Region of South America and the Lesser Antilles descended from a single hybridization event. Second, G. underwoodi and G. cryptus share derived similarities in nucleotide sequences of the maternally inherited mitochondrial DNA, suggesting that the female participant in the hybridization event that produced the hybrid species was either G. cryptus or most closely related to it. Last, phylogenetic analyses recovered historical structure among population samples of G. speciosus supporting previous claims that there is unrecognized diversity under that binomial, and some analyses suggest that G. speciosus does not comprise a natural group.     

RFLP analysis of phylogenetic relationships and genetic variation in the genus Lycopersicon

Summary Forty single-copy, nuclear probes of known chromosomal position were used to examine restriction fragment length polymorphism in the tomato genus Lycopersion. The probes were from three libraries: one cDNA, and two genomic libraries ne genomic made with EcoRI and the other with PstI. Total DNA from 156 plants representing eight species was cut with five different restriction enzymes and scored in 198 probe-enzyme combinations. Genetic distances between accessions (populations) and species were calculated from the resultant restriction patterns and proportion of shared bands. Accessions belonging to the same species largely clustered together, confirming their current classification. However, one mountain accession, classified as L. peruvianum var. humifusum (LA2150), was sufficiently distinct from the other accessions of L. peruvianum that it may qualify as a separate species L. esculentum and L. pimpinellifolium were the least clearly differentiated, possibly reflecting introgressive hybridization, known to have been promoted by man in recent history. Dendrograms constructed from cDNA versus genomic clones were nearly identical in their general grouping of species. The dendrograms revealed two major dichotomies in the genus: one corresponding to mating behavior [self-compatible (SC) versus self-incompatible (SI) species] and the other corresponding to fruit color (red versus green-fruited species). The ratio of withinversus between-accession diversity was much lower for SC species, indicating that most of the diversity within these species exists between populations, rather than within populations. Overall, the amount of genetic variation in the SI species far exceeded that found in SC species. This result is exemplified by the fact that more genetic variation could be found within a single accession of one of the SI species (e.g., L. peruvianum) than among all accessions tested of any one of the SC species (e.g., L. esculentum or L. pimpinellifolium). Results from this study are discussed in relationship to germ plasm collection/utilization and with regard to the use of RFLPs in tomato breeding and genetics.