DNA sequences identify invasive alien Cardamine at Lake Constance

The shores of Lake Constance in southwest Germany inhabit an endemic and highly endangered lake-shore community. In spring 2004, a so far unknown Cardamine (Brassicaceae) was detected at the lake-shores. In the subsequent years, this taxon has spread rapidly, 95 locations have been recorded until spring 2007. We tested the utility of DNA sequences to distinguish between two alternative hypotheses regarding the appearance of this new invasive taxon: a local formation via hybridization between native species versus an introduction of a non-native taxon. The relative DNA contents was analysed as an additional independent character. DNA sequences provided substantial evidence that the unknown Cardamine taxon, recently discovered at Lake Constance in southwest Germany, is a non-native species introduced from abroad. Sequences of the internal transcribed spacer of the large subunits of nuclear ribosomal DNA and two noncoding regions of chloroplast DNA (trnL intron, trnL/F spacer) were distant from sequences of all native Cardamine species providing evidence against a hybridization hypothesis. In contrast, DNA sequences of the unknown Cardamine were identical to one accession of Cardamine flexuosa auct. non With. (Asian C. flexuosa) from Japan. The introduction history of Asian C. flexuosa at Lake Constance and the potential threat to the native lake-shore vegetation is discussed. Our study highlights the potential of DNA sequences to identify invasive genotypes and source regions.     

Phylogeography of the Japanese eight-barbel loach <Emphasis Type="Italic">Lefua echigonia</Emphasis> from the Yamagata area of the Tohoku district,Japan

The Japanese eight-barbel loach Lefua echigonia, which is a freshwater fish native to Japan, is distributed from the Tohoku to Kinki districts and is divided into six regional populations according to mtDNA analysis. In this study, we investigated L. echigonia collected from several locations in Yamagata Prefecture and neighboring prefectures using mtDNA control region sequences and confirmed the spatial distribution pattern among the new regional population (Yamagata population). The new population was limited to the Mogami river system in the inland area of Yamagata Prefecture and is distinguished from other regional populations by high sequence divergences.     

Assessment of the global paradigms of genetic variability in Strongyloides stercoralis infrapopulations determined by mitochondrial DNA sequences

Microevolutionary data of Strongyloides stercoralis infrapopulations are regarded as a requirement for determining the global genetic structure and transmission paradigms of this neglected tropical nematode among the neighboring countries of the world. English databases were searched from 2010 to 2019, analyzing a total of 10 publications. The cytochrome c oxidase subunit 1 sequences of S. stercoralis isolated from Asian and African continents were subjected to calculate the diversity indices and genetic differentiation. A parsimonious haplotype network indicated a star-like trait a total of 106 (Homo sapiens) and 48 haplotypes (Canid) being grouped into four distinct geographical haplogroups. A significant genetic diversity was identified in human-derived S. stercoralis (Haplotype diversity: 0.78) and those with dog (Hd: 0.86) origins. Cladistic phylogenetic tree indicated the Japanese, Thailandish, and Myanmarese clades have a sister relationship with the Laotian clade. The statistically significant Fst values indicated that human S. stercoralis populations of Japanese-Thailandish, Japanese-Myanmarese, and Japanese-Laotian origins were genetically differentiated (Fst: 0.48430 to 0.54903). We conclude that a high gene migration of human strongyloidiasis is being unequivocally shared between the Laotion-Myanmarese and Laotion-Thailandish population pairs. The current findings enhance our knowledge to assess the transmission dynamics and the evolutionary patterns of S. stercoralis in various geographical regions of the globe; also it will serve as a basis for public health policy to control human strongyloidiasis particularly in immunocompromised individuals. Besides, the infected canids and other environmental reservoirs for zoonotic transmission of S. stercoralis to humans should be de-wormed along with their owners.     

东亚森林种群遗传结构及迁移扩散模式

东亚是温带植物种丰度的热点地区,它与北美东部具有相似的气候和植物组成,但是物种丰度是北美东部的2倍。第四纪冰期和间冰期反复的气候变动形成了当今北半球温带物种的分布格局与遗传结构,反复的气候波动导致海平面的反复升降,为东亚地区物种扩张提供了路线,导致种群不断的分开和连接,从而促进了进化的发生和异域物种的形成。介绍了森林树种的群体遗传学研究及分子系统地理学研究情况,阐述了东亚地区森林树种迁移扩散研究概况,包括物种迁移扩散模式及森林树种天然种群在东亚的迁移扩散情况,最后展望了该研究领域的发展趋势。     

Phylogeography of the Bitter Apple, <Emphasis Type="Italic">Citrullus Colocynthis</Emphasis>

Citrullus colocynthis is a desert plant with a rich history as an important medicinal plant and as a source of valuable oil. Its small seeds appear in several early Egyptian, Lybian and Near Eastern sites from about 4000 BC. Sequence information deduced from several polymorphic intergenic cpDNA regions and a relatively large intron (0.6 kb) at the transit sequence of single-copy nuclear gene G3pdh showed clear geographical structure among C. colocynthis accessions. Region specific haplotypes with different nucleotide substitution rates were observed. The highest number of substitution events occurred in C. colocynthis selections from India and Pakistan, the lowest number in accessions from the Middle Eastern and West Asian region (Iran, Israel, and Afghanistan). Population level variation at the noncoding cpDNA and G3pdh intron are congruent. Indels at two cpDNA regions and unique nuclear and cpDNA substitutions indicate the direction of migration from the African continent into the Middle East and the Far East. C. colocynthis collected in Australia showed the highest sequence homology with accessions from Cyprus and Morocco. Divergent lineages are restricted to portions of the species range. Possible causes of this pattern include restricted migration and gene flow between regions, and differences in population size of divergent haplotypes based on differential patterns of environmental adaptation.     

New members to Arctic-like lineage of canine distemper virus from Turkey

Canine distemper virus (CDV) causes a multisystemic fatal disease, briefly named as distemper, in domestic and wild animals. Molecular characterization studies serve to identify local strains, accordingly, helps to determine the scope of vaccination in prevention of distemper. We aimed with this study to update the molecular status of CDV in domestic dogs in Turkey.Sequence analysis of the H gene revealed that novel Turkish sequences formed a separated clade in Arctic-like lineage. Italian clade which mainly included strains originated from wild canid or non-canid localized nearly to novel Turkish clade. Codons 530th and 549th determining the affinity of domestic or wild animals to distemper were Asparagine and Tyrosine, respectively.This report presented the presence of CDV strains belonging to Arctic-like lineage for the first time in domestic dogs in Turkey. The findings pave the way for the reassessment of the circulation and geographical shifting of Arctic-like lineages of CDV.     

Taxonomic status and intraspecific phylogeography of two sibling species of Metaphire (Oligochaeta: Megascolecidae) in Taiwan

In this study the synonymy of Amynthas formosae (Michaelsen, 1922) and A. yuhsii (Tsai, 1964) are reevaluated and the intraspecific phylogeography between them is studied. The morphological comparison and phylogenetic analysis based on cytochrome c oxidase subunit I suggest that A. formosae and A. yuhsii are not synonyms and both of them belong to Metaphire. The phylogeographic analysis suggests that the formation of mountains and rivers during the uplift of the Western Foothills in Taiwan comprised the vicariance events responsible for the intraspecific genetic differentiation between these two species.     

Is the western population of the European mink, (Mustela lutreola), a distinct Management Unit for conservation?

The European mink (Mustela lutreola) is one of the most threatened carnivores in Europe, with fragmented populations in Belarus, Russia and Romania, as well in south-western France and northern Spain. Many populations have become extinct recently, or are declining. We investigated mitochondrial DNA variation, using the complete D-loop region, and concentrating on the west European population. The aim was two-fold: to use the genetic information to advise on the conservation of European mink, and to begin to understand their history through the Pleistocene. Captive breeding and re-introduction programmes are underway, so it is particularly vital to know whether the West European population should be treated separately. We find that European mink probably colonised from a single refugium after the last glaciation. West European populations may be fixed for a single haplotype, also suggesting a common origin. Despite this evidence for gene flow, following the precautionary principle we suggest that mink from the three geographically separate populations (Romania, Eastern and Western Europe) should be managed separately, for the moment.     

Prevalence and dispersal of a facultative bacterial symbiont associated with an endemic metazoan host

Co-dispersal is of primary importance in symbiotic relations between macro- and micro-organisms. Obligate symbionts generally follow the same dispersal pattern as their host, while it still remains unresolved whether hosts and their facultative symbionts follow the same dispersal patterns. Here we addressed the question of symbiont and host co-dispersal by analyses of the earthworm Lumbricus terrestris, and its facultative bacterial symbiont Verminephrobacter. We analyzed co-dispersal by direct sequence-based typing of the earthworm mitochondrial ND4, and the symbiont adk genes, respectively. A total of 96 earthworms from Norwegian (n = 20), German (n = 20), English (n = 31) and Canadian (n = 25) populations were analyzed. We found that the earthworms were mainly endemic, while the symbiont showed a more complex dispersal pattern. The symbiont showed a significant difference in prevalence between the geographic regions. In addition, we found a low degree of co-evolution between host and symbiont, with some of the symbiont sequence types being globally distributed. Future research, however, is needed to resolve whether the symbiont is truly globally distributed, in contrast to its endemic host.     

Conservation of highly fragmented systems: The north temperate Alexander Archipelago

The Alexander Archipelago of Southeast Alaska encompasses over 2000 named islands that extend along 600 km of the North Pacific Coast. This review summarizes recent research on mammals of this largely unexplored region. Field inventories followed by preliminary molecular genetic analyses of selected mammals demonstrate substantial spatial structure consistent with both the dynamic geologic history of this boreal region and the highly insular landscape. New views of taxonomic diversity, biogeographic history, and contemporary population connectivity lay a framework for managing and conserving this complex biome. First, repeated Pleistocene glacial advances along the coast fragmented species, leaving clear genetic signatures and a strongly diversified fauna. Organisms recolonized the coast following deglaciation from multiple northern (Beringia), southern (West Coast and Continental) or North Pacific Coastal refugia. Several species are composed of multiple, genetically distinctive lineages (in some cases, incipient or new species) due to independent colonization histories from distinct, divergent source populations. Second, the insular landscape of the Alexander Archipelago has produced highly endemic populations. These centers of endemism should be thoughtfully managed as hotspots of lineage diversity. Until a better understanding of connectivity among these divergent populations is developed, each island should be considered an independent biological unit. Finally, industrial logging, mining, human encroachment, tourism, wildlife consumption, and invasive species should be stringently monitored and regulated with respect to impact on island endemics and ecosystems. A new conservation paradigm for the Tongass National Forest should be developed that is built around the recognition of the complexity of this incomparable island archipelago of the North Pacific. In particular, recognition of high diversity and endemism should be central to management plans.