Origin of domesticated water chestnuts (Trapa bispinosa Roxb.) and genetic variation in wild water chestnuts.

The water chestnut Trapa bispinosa Roxb. has been domesticated in China and has been reported as the only domesticated species of this genus. To understand the origin of T. bispinosa and its evolution pathway, we compared the genetic similarity and seed morphology of domesticated water chestnut T. bispinosa with three wild species T. natans, T. incisa, and T. japonica along with archeological seed samples from the Tianluoshan site (approximately 7000-6300 cal BP) in China. The largest seed size was observed only in the domesticated species, whereas other wild species showed smaller size including T. natans L. genetically close to the domesticated type, and T. incisa was the smallest in size. The volumes of the seed capsule and endosperm were measured using X ray CT scans, showing the ratios of total volumes between T. bispinosa and wild species ranged from 4.2 to 4.5. The ratios of endosperm volume ranged from 3.3 to 3.7. Both measurements showed domesticated species have larger seed volume. Genome size was indirectly estimated by flow cytometry. Domesticated species with larger seed size was estimated as diploid, as were the wild species except for tetraploid species T. japonica. Domesticated species clearly showed the largest edible organs, but it was not a result of ploidy level changes. Maternal lineages traced using complete whole chloroplast sequences, suggested that T. natans is the closest to T. bispinosa, both of which are close to T. japonica. The result was confirmed by PCR genotyping with chloroplast insertion/deletion (cpINDEL) markers developed in the study. T. incisa showed distinct plastid types within the species, and T. japonica showed a unique plastid genotype. Our study concludes the largest volumes for the edible endosperm have been accomplished through nearly 6000 years of artificial selection, but the domestication did not involve ploidy level changes.

Studying Genetic Diversity and Relationships between Mountainous Meihua Chickens Using Mitochondrial DNA Control Region.

The Mountainous Meihua chicken is a unique regional germplasm resource from Tongjiang County, Bazhong City, China, but its genetic structure and evolutionary relationships with other native chicken breeds in the Sichuan region remain unclear. Here, we analyzed a total of 469 sequences, including 199 Mountainous Meihua chicken sequences generated in this study, together with 30 sequences representing 13 clades and 240 sequences from seven different Sichuan local chicken breeds downloaded from NCBI. These sequences were further used to analyze genetic diversity, patterns of population differentiation, and phylogenetic relationships between groups. We show that Mountainous Meihua chicken mtDNA sequences have high haplotypic and nucleotide diversity (0.876 and 0.012, respectively) and with a T bias that is suggestive of good breeding potential. Phylogenetic analysis showed that Mountainous Meihua chickens belong to clades A, B, E, and G and have a low affinity to other chicken breeds, with a moderate degree of differentiation. A non-significant Tajima's D indicates that no demographic expansions occurred in the past. Finally, the four maternal lineages identified in Mountainous Meihua chicken showed unique genetic characteristics.

Maternal lineage of Nicobari pig (Sus scrofa nicobaricus) correlated with migration of Nicobarese, a native tribal population of Andaman and Nicobar Islands, India.

Nicobari pig is reared by Nicobarese, a native tribal population of Andaman and Nicobar Islands. Nicobari pig has maintained its genetic identity due to geographical isolation. This communication is the first report on maternal inheritance of Nicobari pigs. DNA polymorphism data showed seven haplotypes. D-loop sequence information and mitogenome analysis were able to earmark Nicobari pigs to Asian clade. The domestication process of pigs and its expansion pattern help to understand human migration pattern. Based on this hypothesis, this communication elucidates the probable origin of Nicobarese. Earlier studies indicated that Nicobarese had genetic affinities to races distributed in China, Malaysia and Thailand. Our data on maternal inheritance of Nicobari pig correlates with the data on migration of Nicobarese. Moreover, we could establish a novel connection of Nicobarese with people of Northeastern parts of India, Philippines and Vietnam through phylogenetic signal and geographical provenance of Nicobari pig. We further concluded that migration of Nicobarese happened during Western route of migration (WRM) ∼4000 years before present. Therefore, we propose one wave hypothesis of peopling of Nicobar based on our study and existence of Ausrtroasiatic language, Mon-Khmer in these islands.

Mitochondrial DNA diversity divulges high levels of haplotype diversity and lack of genetic structure in the Indian camels.

Camels represent an important genetic resource of the desert ecosystems of India, with the dromedary and Bactrian camels inhabiting the hot and cold deserts, respectively. This study is the first attempt to investigate mitochondrial DNA based genetic diversity in the Indian camel populations and explores their relationship in the context of global genetic diversity of all the three large camel species (Camelus ferus, Camelus bactrianus and Camelus dromedaries). A mitochondrial DNA fragment encompassing part of cytochrome b gene, tRNAThr, tRNAPro and the beginning of the control region was amplified and analyzed in 72 dromedary and 8 Bactrian camels of India. Sequence analysis revealed that the haplotype and nucleotide diversity (Hd: 0.937 and π: 0.00431) in the Indian dromedaries was higher than the indices reported so far for the dromedary or Bactrian camels across the globe. The corresponding values in the Indian Bactrian camels were 1.000 and 0.00393, respectively. Signals of population expansion were evident in the dromedaries of India on the basis of mismatch analysis and Fu's Fs values. The analysis of molecular variance attributed most of the genetic variance (92.15%) between the dromedary, wild Bactrian and domestic Bactrian camels indicating separate maternal origins. The existence of three mitochondrial lineages in the old world camels (C. bactrianus: Lineage A; C. ferus: Lineage B and C. dromedarius: Lineage C) was also substantiated by the topology of the Median-Joining network.

Ancient Mitogenomes Provide New Insights into the Origin and Early Introduction of Chinese Domestic Donkeys.

Both molecular data and archaeological evidence strongly support an African origin for the domestic donkey. Recent genetic studies further suggest that there were two distinct maternal lineages involved in its initial domestication. However, the exact introduction time and the dispersal process of domestic donkeys into ancient China are still unresolved. To address these questions, we retrieved three near-complete mitochondrial genomes from donkey specimens excavated from Gaoling County, Shaanxi Province, and Linxia Basin, Gansu Province, China, dated at 2,349-2,301, 469-311, and 2,160-2,004 cal. BP, respectively. Maximum-likelihood and Bayesian phylogenetic analyses reveal that the two older samples fall into the two different main lineages (i.e., clade Ⅰ and clade Ⅱ) of the domestic donkey, suggesting that the two donkey maternal lineages had been introduced into Midwestern China at least at the opening of Silk Road (approximately the first century BC). Bayesian analysis shows that the split of the two donkey maternal lineages is dated at 0.323 Ma (95% CI: 0.583-0.191 Ma) using root-tip dating calibrations based on near-complete mitogenomes, supporting the hypothesis that modern domestic donkeys go back to at least two independent domestication events. Moreover, Bayesian skyline plot analyses indicate an apparent female population increase between 5,000 and 2,500 years ago for clade I followed by a stable population size to the present day. In contrast, clade II keeps a relatively stable population size over the past 5,000 years. Overall, our study provides new insights into the early domestication history of Chinese domestic donkeys.

Spatial genetic structure and Ovis haplogroup as a tool for an adaptive conservation management of the endangered Cyprus mouflon.

The mouflon (Ovis gmelini ophion) is the largest wild terrestrial mammal of Cyprus. Regarded as the local flagship species, its population range is limited to the mountainous Paphos Forest and adjacent areas including part of Troodos National Forest Park (> 700 Km2). This species, protected by both national and international legislation, is classified as Endangered by the IUCN, with livestock intrusion, poaching and habitat loss as the main threatening factors. We determined the spatial genetic structure by investigating sexes separately and shed further light on the Cyprus mouflon placement among Ovis haplogroups (HGs) to enforce its protection within an adaptive conservation framework. We genotyped 108 samples collected across the entire species' range at both14 loci of the microsatellite DNA and the mitochondrial DNA Control Region (CR). Microsatellite genotyping indicated that the wild population retained low genetic variability, which, however, was not associated with a level of inbreeding raising particular concern (FIS = 0.12). An overall weak spatial genetic structure was disclosed, consistently with the limited extension of the mouflon range, the lack of significant physical barriers to dispersal and the intense gene flow mostly occurring along a northeast-southwest axis across the forest. Nevertheless, evidences of structure were found for females in compliance with their philopatric behaviour. The disclosure of unique features compared to Mediterranean and Near East conspecifics, such as the occurrence of a six-fold 76 bp-long repeated motif in the Cyprus mouflon CR, along with the outcome of a phylogenetic reconstruction (based on a far higher number of Ovis GenBank records and Cyprus haplotypes than in previous studies) inspired the proposal of a new haplogroup (HGC2) which included the Anatolian mouflon (O. g. anatolica, former HGX) as sister taxon. While both high habitat heterogeneity and low human disturbance were the main drivers in determining the overall spatial structure, future conservation efforts to preserve this valuable genetic resource should focus on avoiding possible introgressive hybridisation with co-grazing livestock to the edge of its range.

Complete mitogenome of Kashmir musk deer (Moschus cupreus) and its comparative phylogenetic relationships.

Kashmir musk deer, Moschus cupreus (KMD) is one the most threatened species endemic to the Himalayan region of Kashmir, Pakistan and Afghanistan. Herein, we have sequenced, annotated and characterized the complete mitogenome of M. cupreus. The investigation and comparison of the mitogenome provide crucial information for phylogenetic analysis to understand the evolutionary relationships. The mitogenome of KMD was 16,354 bp long, comprising 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and non-coding control region. Its composition was highly A+T biased 68.42%, and exhibited a positive AT-skew (0.082) and negative GC-skew (- 0.307). The phylogenetic analysis suggested that KMD was a primitive and extant species in the genus Moschus, whereas Alpine musk deer (M. chrysogaster) and Himalayan musk deer (M. leucogaster) were the closest relatives. It indicated the placement of M. cupreus within the monotypic family Moschidae of musk deer. Hence, it provides a better understanding of lineage identification and musk deer evolution for further research.

Phylogeography and Phylogenetic Evolution in Tibetan Sheep Based on MT-CYB Sequences.

To date, molecular genetics and population studies in Tibetan sheep (Ovis aries) have been limited, and little is known about the phylogenetic evolution and phylogeography of Tibetan sheep populations. The aim of the present research was to explore phylogeography and phylogenetic evolution of Tibetan sheep populations, on the basis of mitochondrial DNA (mtDNA) gene MT-CYB (1140 base pairs). Our dataset consisted of 641 MT-CYB sequences from the same amount of animals belonging to 15 populations of Tibetan sheep living in the Qinghai-Tibetan Plateau, China. Haplotype and nucleotide diversities were 0.748 ± 0.010 and 0.003 ± 0.001, respectively. The analysis of phylogeography revealed the presence of two formerly described haplogroups in 15 populations of Tibetan sheep, however only one haplogroup was present in Awang sheep. Moreover, 641 Tibetan sheep were distributed into a minimum of two clusters by clustering analysis. The 15 Tibetan sheep populations and 19 reference populations of 878 individuals were separated into six main groups based on their substitutions per site, from which we constructed a phylogenetic tree. Minor differences in branching order of various taxa between trees acquired from either gene were observed. This study provides insights on the origins and phylogenetic evolution of populations residing in the Qinghai-Tibetan Plateau, which will aid information of future conservation programs aimed at conserving this valuable genetic resource.

Transgenerational effects of early environmental insults on aging and disease incidence.

Adverse early life experiences are major influences on developmental trajectories with potentially life-long consequences. Prenatal or early postnatal exposure to stress, undernutrition or environmental toxicants may reprogram brain development and increase risk of behavioural and neurological disorders later in life. Not only experience within a single lifetime, but also ancestral experience affects health trajectories and chances of successful aging. The central mechanism in transgenerational programming of a disease may be the formation of epigenetic memory. This review explores transgenerational effects of early adverse experience on health and disease incidence in older age. First, we address mechanisms of developmental and transgenerational programming of disease and inheritance. Second, we discuss experimental and clinical findings linking early environmental determinants to adverse aging trajectories in association with possible parental contributions and sex-specific effects. Third, we outline the main mechanisms of age-related functional decline and suggest potential interventions to reverse negative effects of transgenerational programming. Thus, strategies that support healthy development and successful aging should take into account the potential influences of transgenerational inheritance.

Genetic diversity among perennial wild rice Oryza rufipogon Griff., in the Mekong Delta.

Oryza rufipogon Griff. is a perennial species of wild rice widely distributed along the channels and rivers of the Mekong Delta, Vietnam. This study attempted to find centers of diversity among wild rice populations in this area and their inter-relationships. The highest genetic diversity was found in the Dong Thap population and the lowest in the Can Tho population. Maternal diversity evaluated using chloroplast INDELs detected ten plastid types, five of which were novel relative to other Asian countries. The mitochondrial genome suggested two unique deletions. One 699-bp deletion via short tandem repeats was accompanied by another deletion including orf153. All accessions carrying the mitochondrial type were found in a particular plastid type. This unique maternal lineage was confined to specific channels where it showed vigorous vegetative growth in comparison to upstream areas where various maternal lineages and maximum genetic diversity occurred. This area along the Mekong Delta is a center of not only nuclear but also maternal diversity.