Phylogeography of the Mauremys mutica complex and the implications for conservation management.

For more than three decades, the Asian turtle crisis has resulted in the decline of every native species in China. For some species, such as the yellow pond turtle (Mauremys mutica), wild populations have dwindled to near functional extinction. Previous studies show there is deep genetic divergence of M. mutica sensu lato between populations north and south of the Pearl River Drainage but no data to show if phylogeographic structure occurs within these two main types. In this study, we found clear phylogeographic structure. In northern types, we found two main clades, corresponding to mainland China and island clades (Taiwan and Yaeyema Islands) with uncorrected p values of 0.00-2.0% divergence in our 2353 bp concatenated mtDNA data set. For the southern types, we found three main clades corresponding to Hainan, Mainland (Vietnam/Guangxi) and the Annam pond turtle (Mauremys annamensis) with divergence ranging from 1.0-1.8% among these three groups. Moreover, the identification of northern and southern types by phenotype was roughly 98% accurate, which, coupling with the deep genetic divergence in mtDNA (5.5-6.7%) and in the 6056 bp nuDNA data set (0.16-0.37%) provide sufficient evidence for northern M. mutica to be an independent species, and individuals from the southern clade should be regarded as subspecies of M. annamensis. Finally, we provide the most comprehensive database to date which can be used to determine the region of origin for captive stock. Making the large captive populations of M. mutica, under the right conditions, potentially valuable for restocking or augmentation of wild populations.

Tree House Explorer: A Novel Genome Browser for Phylogenomics

Tree House Explorer (THEx) is a genome browser that integrates phylogenomic data and genomic annotations into a single interactive platform for combined analysis. THEx allows users to visualize genome-wide variation in evolutionary histories and genetic divergence on a chromosome-by-chromosome basis, with continuous sliding window comparisons to gene annotations, recombination rates, and other user-specified, highly customizable feature annotations. THEx provides a new platform for interactive phylogenomic data visualization to analyze and interpret the diverse evolutionary histories woven throughout genomes. Hosted on Conda, THEx integrates seamlessly into new or pre-existing workflows.

Genetic diversity of yield related traits in a large subset of exotic and indigenous rice germplasm collection maintained at Tamil Nadu Agricultural University gene bank

The present investigation was carried out to explore the extent of genetic divergence in 95 rice germplasm accessions for twelve characters during kharif, 2018. In D2 analysis, the 95 genotypes were grouped into fifteen clusters. The clustering pattern indicated that there was no parallelism between genetic diversity and geographical origin as the genotypes from same origin were included in different clusters and vice versa. The highest intra cluster distance was registered in cluster V (215.183) followed by cluster IX (209.831), cluster VIII (204.057) and cluster XIV (202.623).The maximum inter cluster distance was observed between cluster II and cluster III (991.049) followed by cluster II and cluster X (974.960), cluster III and cluster XI (963.826), cluster II and XII (962.013), cluster X and cluster XI (932.469) and cluster XI and cluster XII (919.151). Genetically distant parents from those clusters could be able to produce higher heterosis in progenies on hybridization. Grain yield per plant, 100 grain weight and days to 50% flowering were the major contributors towards the total genetic divergence among the genotypes studied. Thus selection could be made based on grain yield per plant, hundred grain weight and days to 50%flowering for the progenies identified.

Demographic history and range modelling of the East Mediterranean Abies cilicica

The Mediterranean Basin is one of the 36 global hotspots of biodiversity and it is rich in endemic tree species. The complex geological history of the region throughout the Neogene and Quaternary periods that were marked with several palaeoclimatic transformations was a major factor triggering the genetic divergence of lineages in tree species in the region. The ongoing global climate change is the main factor threatening Mediterranean biodiversity. The risk of population decline related to aridization is the highest in the case of endemics, especially for cold-adapted conifers, such as Abies cilicica. The Cilician fir grows in the East Mediterranean mountains that constitute a local centre of endemism within the region. The species range is fragmented and small-size populations prevail. Previous studies have suggested that the last glacial cycle led to a significant reduction in the species range and might have initiated genetic divergence. As a result, two lineages are currently recognized at the subspecies level, A. cilicica subsp. isaurica (Turkey) and A. cilicica subsp. cilicica (Turkey, Syria, and Lebanon). The predictions about the impact of future climate changes in the East Mediterranean suggest a profound reduction of precipitation and overall warming that may put the remnant populations of A. cilicica at a risk of decline. Here, we used the Bayesian approach to investigate the demographic history of endemic A. cilicica. Specifically, we estimated the probable time of the intraspecies divergence to verify previous assumptions about the species’ evolutionary history. Additionally, niche modelling was used to outline the potential range of changes in the past and to indicate glacial refugia in where the species persisted climate crisis. This approach was also used to explore the possible influence of the future climate changes on the distribution of A. cilicica in the region. Our results demonstrate that the divergence between the Lebanese and the Turkish populations that occurred ~220 ka years BP coincided with the Riss glaciation. According to palaeoecological data, in the East Mediterranean, that glacial period caused a severe reduction in the populations of woody species due to the aridity of the climate. At that time, the Lebanese-Syrian part of the range was likely disconnected from the main range. The second split was induced by the last glacial cycle ~60 ka years BP and led to the separation of the Central Taurus and East Taurus population and, consequently, to the formation of the two subspecies. Niche modelling for the last glacial maximum has allowed us to locate the probable refugia for A. cilicica in the western Anatolia and Syria-Lebanon area. A projection of the future possible distribution of the species indicates a serious reduction of the range during this century.

ASSESSMENT OF ECOLOGICAL AND GENETIC DIVERSITY OF THE GENUS VIGNA SAVI USING BIOTECHNOLOGICAL METHODS - ISSR MARKERS

The world's genetic resources of plants are the main source of improving crops for decades to come. The gene pool of plants has a hidden resource of new genes, or their combinations, including - selection-important features. The study of the potential of the plant gene pool with the main biological and economic characteristics allows to expand the genetic base of crops for the successful implementation of breeding programs in various areas. The genus Vigna has about 200 species that are grown in warm regions of the planet. The centers of origin of the species are in Africa, but mung beans, urd, azuki and rice beans are of Asian origin. The collection includes 20 specimens belonging to 7 species of the genus Vigna: V. aconitifolia (Jacq.) Marechal (willow aconitolista, mott) – 3 specimens, V. angularis (Willd.) Ohwi et Ohashi (adzuki) – 4, V. radiata (L.) R. Wilczek (mash) – 4, V. umbellata (Thunb.) Ohwi et Ohashi (vigna rice) – 4, V. unguiculata (L.) Walp. (Chinese) – 5. These are mainly local varieties, about 10 % are breeding varieties and 1% are forms that grow in nature. The multifaceted use of cultivated species of the genus Vigna contributed to their spread throughout the tropical, subtropical and temperate zones of the globe. They are economically important crops in many developing countries. Geographical analysis showed that most of the samples came from the areas of world agriculture and crop formation. most samples of V. radiata, V. mungo, V. aconitifolia, V. trilobata, V. umbellata were obtained from India and Pakistan, V. angularis – from East Asia and China, V. unguiculata – East Africa (Ethiopia, Kenya), V unguiculata – from China. However, the exact place of domestication of this culture has not been established, and in numerous sources of literature can be found different opinions of scientists on the origin of cowpea and the centers of its diversity. Recently, using the methods of molecular genetics (RAPD, AFLP and others) it was confirmed that the northern part of Africa is the center of origin of the cultured, because the wild types of West Africa are closer to cultural forms than the wild types of East and South Africa. It should be noted that the species of cowpea have a significant intraspecific polymorphism. The samples showed strong variability of morphological and economically valuable features. Such a wide range of variable variability is due to the places of cultivation of samples, different environmental conditions (plains, mountains, climate). According to the results of the evaluation of the DNA polymorphism of cowpea using molecular genetic markers, it was found that the species of cowpea involved in the study are characterized by a high level of DNA polymorphism, which averaged 78.6 %. 145 loci were identified, including 31 unique, specific to a particular sample, and 31 monomorphic, characteristic of all samples. Monomorphic loci are conserved regions of DNA that indicate the common origin of the species of cowpea involved in the work, and can be used as genus and species-specific markers. Unique loci indicate genetic divergence of the studied material and can serve as markers of certain samples. The average level of intrapopulation polymorphism of cowpea DNA (37.2–93.8 %, depending on the genotype) was established, which indicates the existence of significant variability in the studied samples of cowpea. It shows a high level of genetic divergence of cowpea species and testifies in favor of the polyphyletic theory of their origin.

Landscape genetics across the Andes Mountains: Environmental variation drives genetic divergence in the leaf-cutting ant Atta cephalotes

Disentangling the mechanisms underlying spatial distribution of genetic variation into those due to environment or physical barriers from mere geographic distance is challenging in complex landscapes. The Andean uplift represents one of the most heterogeneous habitats where these questions remain unexplored as multiple mechanisms might interact, confounding their relative roles. We explore this broad question in the leaf-cutting ant Atta cephalotes, a species distributed across the Andes Mountains using nuclear microsatellite markers and mtCOI gene sequences. We investigate spatial genetic divergence across the Western range of Northern Andes in Colombia by testing the relative role of alternative scenarios of population divergence, including geographic distance (IBD), climatic conditions (IBE), and physical barriers due to the Andes Mountains (IBB). Our results reveal substantial genetic differentiation among A. cephalotes populations for both types of markers, but only nuclear divergence followed a hierarchical pattern with multiple models of genetic divergence imposed by the Western range. Model selection showed that IBD, IBE (temperature and precipitation), and IBB (Andes mountains) models, often proposed as individual drivers of genetic divergence, interact, and explain up to 33% of genetic divergence in A. cephalotes. IBE models remained significant after accounting for IBD, suggesting that environmental factors play a more prominent role when compared to IBB. These factors in combination with idiosyncratic dispersal patterns of ants appear to determine hierarchical patterns of gene flow. This study enriches our understanding of the forces shaping population divergence in complex habitat landscapes.