Phylogenetic relationship analysis of Iranians and other world populations using allele frequencies at 12 polymorphic markers

The estimation of genetic distance between populations could improve our viewpoint about human migration and its genetic origin. In this study, we used allele frequency data of 12 polymorphic markers on 250 individuals (500 alleles) from the Iranian population to estimate genetic distance between the Iranians and other world populations. The phylogenetic trees for three different sets of allele frequency data were constructed. Our results revealed the genetic similarity between the Iranians and European populations. The lowest genetic distance was observed between the Iranians and some populations reside in Russia. Furthermore, the high genetic distance was observed between the Iranians and East Asian populations. The data suggested that the Iranians might have relatively close evolutionary history with Europeans, but historically independent from East Asian populations. The evaluation of genetic distance between Indians populations and Iranians was also performed. The Indian groups showed low genetic distance with others, but high genetic distance with the Iranians. This study could provide a new insight into the evolutionary history of the Iranian population.     

The genetic relationship among Iranian ethnic groups: an anthropological view based on HLA class II gene polymorphism

Highly polymorphic human leukocyte antigen (HLA) genes are considered as useful markers by molecular anthropologists to determine genetic relationship among populations. This review summarizes the results of molecular analyses of HLA class II gene polymorphism in 816 DNA samples from 11 Iranian ethnic groups. The genetic relationship of Iranians to Asians and Europeans has also been reported here. The results of this study revealed a close genetic relationship among Iranian subpopulations which were well separated from other Asian and European populations, however, a genetic similarity was observed among Iranians, Macedonians, Greeks, and Italians.     

Genetic Diversity and Population Structure in Polygonum cespitosum: Insights to an Ongoing Plant Invasion

Molecular markers can help elucidate how neutral evolutionary forces and introduction history contribute to genetic variation in invaders. We examined genetic diversity, population structure and colonization patterns in the invasive Polygonum cespitosum, a highly selfing, tetraploid Asian annual introduced to North America. We used nine diploidized polymorphic microsatellite markers to study 16 populations in the introduced range (northeastern North America), via the analyses of 516 individuals, and asked the following questions: 1) Do populations have differing levels of within-population genetic diversity? 2) Do populations form distinct genetic clusters? 3) Does population structure reflect either geographic distances or habitat similarities? We found low heterozygosity in all populations, consistent with the selfing mating system of P. cespitosum. Despite the high selfing levels, we found substantial genetic variation within and among P. cespitosum populations, based on the percentage of polymorphic loci, allelic richness, and expected heterozygosity. Inferences from individual assignment tests (Bayesian clustering) and pairwise F _ST values indicated high among-population differentiation, which indicates that the effects of gene flow are limited relative to those of genetic drift, probably due to the high selfing rates and the limited seed dispersal ability of P. cespitosum. Population structure did not reflect a pattern of isolation by distance nor was it related to habitat similarities. Rather, population structure appears to be the result of the random movement of propagules across the introduced range, possibly associated with human dispersal. Furthermore, the high population differentiation, genetic diversity, and fine-scale genetic structure (populations founded by individuals from different genetic sources) in the introduced range suggest that multiple introductions to this region may have occurred. High genetic diversity may further contribute to the invasive success of P. cespitosum in its introduced range.     

Multilocus microsatellite typing shows three different genetic clusters of Leishmania major in Iran

Ten polymorphic microsatellite markers were used to analyse 25 strains of Leishmania major collected from cutaneous leishmaniasis cases in different endemic areas in Iran. Nine of the markers were polymorphic, revealing 21 different genotypes. The data displayed significant microsatellite polymorphism with rare allelic heterozygosity. Bayesian statistic and distance based analyses identified three genetic clusters among the 25 strains analysed. Cluster I represented mainly strains isolated in the west and south-west of Iran, with the exception of four strains originating from central Iran. Cluster II comprised strains from the central part of Iran, and cluster III included only strains from north Iran. The geographical distribution of L. major in Iran was supported by comparing the microsatellite profiles of the 25 Iranian strains to those of 105 strains collected in 19 Asian and African countries. The Iranian clusters I and II were separated from three previously described populations comprising strains from Africa, the Middle East and Central Asia whereas cluster III grouped together with the Central Asian population. The considerable genetic variability of L. major might be related to the existence of different populations of Phlebotomus papatasi and/or to differences in reservoir host abundance in different parts of Iran.     

Biodiversity of 52 chicken populations assessed by microsatellite typing of DNA pools

In a project on the biodiversity of chickens funded by the European Commission (EC), eight laboratories collaborated to assess the genetic variation within and between 52 populations from a wide range of chicken types. Twenty-two di-nucleotide microsatellite markers were used to genotype DNA pools of 50 birds from each population. The polymorphism measures for the average, the least polymorphic population (inbred C line) and the most polymorphic population (Gallus gallus spadiceus) were, respectively, as follows: number of alleles per locus, per population: 3.5, 1.3 and 5.2; average gene diversity across markers: 0.47, 0.05 and 0.64; and proportion of polymorphic markers: 0.91, 0.25 and 1.0. These were in good agreement with the breeding history of the populations. For instance, unselected populations were found to be more polymorphic than selected breeds such as layers. Thus DNA pools are effective in the preliminary assessment of genetic variation of populations and markers. Mean genetic distance indicates the extent to which a given population shares its genetic diversity with that of the whole tested gene pool and is a useful criterion for conservation of diversity. The distribution of population-specific (private) alleles and the amount of genetic variation shared among populations supports the hypothesis that the red jungle fowl is the main progenitor of the domesticated chicken.     

Dental polymorphism of the raccoon dog in indigenous and invasive populations: internal and external causation

In total, 721 specimens from eight populations of the raccoon dog Nyctereutes procyonoides across native and colonized areas have been studied. The most polymorphic populations inhabit the European part of Russia and a part of the native area. The raccoon dog from Eastern Poland and the Primorie Far East is characterized by low intrapopulational variability. Quantitative genetic variations in the studied populations indicate a relatively higher level in the population from the Primorie Far East compared to the Southern Vologda and Eastern Poland. The pattern of morphological variability in the raccoon dog is shaped by such factors as the latest phylogenetic history of the species and the structure of the morphotype frequency in the time of the divergence of the populations on both micro-and macro-geographic levels. The influence of geographic and climatic factors forms a well-pronounced trend towards diversification in tooth morphology, which is most probably the consequence of adaptations to changes in the food niche.     

Microsatellite DNA markers indicate three genetic lineages in East Asian indigenous goat populations

The genetic differentiation and phylogenetic relationships of 18 indigenous goat populations from seven East Asian countries were analysed based on data obtained from 26 microsatellite DNA markers. The mean number of alleles (MNA) per population ranged from 2.5 to 7.6, with an average of 5.8. Genetic variability estimated from MNA and heterozygosity (H_E and H_O) were relatively low in coastal and island populations. A heterozygous deficiency within populations (F_IS = 0.054, P < 0.001) and total inbreeding (F_IT = 0.181, P < 0.01) were observed, and genetic differentiation in the populations (F_ST) was 13.4%. The results of Bayesian model‐based clustering and a neighbour‐joining tree based on Nei's genetic distance showed that Asian goat populations could be subdivided into at least the following three genetic clusters: East Asian, Southeast Asian and Mongolian. These results are in close accordance with conventional morphological and geographical classifications and migration history.     

Initial determination of DNA polymorphism of some Primula veris L. populations from Kosovo and Austria

Primula veris L. (Primulaceae) is a long lived perennial and well known pharmaceutical plant, widely collected for these reasons in almost all SE Europe and particularly in Kosovo. The aim of the study is to determine molecular polymorphism of cowslip (P. veris L.) populations from Kosovo. DNA extracted from leaves were  investigated in details for presence of polymorphism. RAPD analyses were conducted using 20 different short primers. Genomic DNA amplification profiles were analyzed and processed using data labelling. Comparison between cowslip populations in genetic composition revealed that samples from Bogaj were too distinct on their own. Molecular variation was observed to be more within populations (73 %) as compared to among populations (27 %). On the other hand, genetic distance of populations revealed that the highest genetic distance is between Leqinat and Maja e Madhe. Mean values of expected heterozygosity were highest in Bogaj population, while lowest in Maja e Madhe population. The obtained results indicated that Bogaj population are more polymorphic. From the obtained data it can be concluded that RAPD markers provided a useful technique to study genetic diversity in P. veris L. populations. This technology allows identification and assessment of the genetic similarities and differences among plant populations.     

Molecular phylogeny of extant horseshoe crabs (Xiphosura, Limulidae) indicates Paleogene diversification of Asian species

Horseshoe crabs are marine invertebrates well known for their exceptionally low rates of diversification during their entire evolutionary history. Despite the low species diversity in the group, the phylogenetic relationships among the extant species, especially among the three Asian species are still unresolved. Here we apply a new set of molecular genetic data in combination with a wide geographic sampling of the intra-specific diversity to reinvestigate the evolutionary history among the four living limulid xiphosurans. Our analysis of the intraspecific diversity reveals low levels of connectivity among Carcinoscorpius rotundicauda lineages, which can be explained by the estuarine-bound ecology of this species. Moreover, a clear genetic break across the Thai-Malay Peninsula suggests the presence of cryptic species in C. rotundicauda. The limulid phylogeny finds strong support for a monophyletic genus Tachypleus and a diversification of the three Asian species during the Paleogene period, with speciation events well separated in time by several million years. The tree topology suggests that the three Asian species originated in central South East Asia from a marine stem group that inhabited the shallow coastal waters between the Andaman Sea, Vietnam, and Borneo. In this region C. rotundicauda probably separated from the Tachypleus stem group by invading estuarine habitats, while Tachypleus tridentatus most likely migrated northeast along the Southern coast of China and towards Japan.     

Phylogeography of a northeast Asian spruce, Picea jezoensis, inferred from genetic variation observed in organelle DNA markers

Range-wide genetic variation of the widespread cold-temperate spruce Picea jezoensis was studied throughout northeast Asia using maternally inherited mitochondrial DNA and paternally inherited chloroplast DNA markers. This study assessed 33 natural populations including three varieties of the species in Japan, Russia, China, and South Korea. We depicted sharp suture zones in straits around Japan in the geographical distribution pattern of mitochondrial haplotypes (GST=0.901; NST=0.934). In contrast, we detected possible extensive pollen flow without seed flow across the straits around Japan during the past population history in the distribution pattern of chloroplast haplotypes (GST=0.233; NST=0.333). The analysis of isolation by distance of the species implied that by acting as a barrier for the movement of seeds and pollen, the sharp suture zones contributed considerably to the level of genetic differentiation between populations. Constructed networks of mitochondrial haplotypes allowed inference of the phylogeographical history of the species. We deduced that the disjunction with Kamchatka populations reflects range expansion and contraction to the north of the current distribution. Within Japan, we detected phylogeographically different types of P. jezoensis between Hokkaido and Honshu islands; P. jezoensis in Honshu Island may have colonized this region from the Asian continent via the Korean peninsula and the species in Hokkaido Island is likely to have spread from the Asian continent via Sakhalin through land bridges. Japanese endemism of mitochondrial haplotypes in Hokkaido and Honshu islands might have been promoted by separation of these islands from each other and from the Asian continent by the straits during the late Quaternary.     

西南地区6种魔芋属植物基于cpDNA序列的遗传多样性研究

研究野生作物资源的遗传变异及分化机制对种质资源的收集与改良具有重要意义。魔芋是我国西南地区的特色经济作物,但由于受到人为活动干扰,野生种群不断衰退。为评估西南地区魔芋属(Amorphophallus)野生群体的遗传多样性,探究代表性物种的系统发育地位,该研究利用3个叶绿体DNA(cpDNA)片段,分析了魔芋6个物种的遗传多样性,重建了种间系统发育关系。结果表明:(1)西南地区野生魔芋群体的遗传多样性普遍较低,虽然单倍型多样性(H_d)均值为0.428,但近一半群体只有1个单倍型,6个物种整体水平上的单倍型多样性在0.704到0.983之间。(2)在6个物种间检测到高水平的遗传分化,遗传分化系数(F_ST)值在0.481到0.967之间。(3)系统发育分析表明,选取的27个魔芋种主要聚成3个分支:非洲分支、东南亚分支和东亚大陆分支。疣柄魔芋(A. paeoniifolius)隶属于东南亚分支,而东亚大陆分支A包含花魔芋(A. konjac)和西盟魔芋(A. krausei),东亚大陆分支B由东亚魔芋(A. kiusianus)、滇魔芋(A. yunnanensis)和东京魔芋(A. tonkinensis)构成。生境隔离与人为干扰造成了西南地区野生魔芋群体较低的遗传多样性,魔芋属东亚大陆分支的分化可能与早期的快速扩张和生态适应有关。该研究为西南地区魔芋资源的合理保护、可持续利用和杂交育种提供了参考资料。     

Phylogeographic structure of the dwarf snakehead (Channa gachua) around Gulf of Tonkin: Historical biogeography and pronounced effects of sea‐level changes

Geological events, landscape features, and climate fluctuations have shaped the distribution of genetic diversity and evolutionary history in freshwater fish, but little attention has been paid to that around the Gulf of Tonkin; therefore, we investigated the phylogeographic structure of the dwarf snakehead (Channa gachua) on Hainan Island and mainland China, as well as two populations in Vietnam. We attempted to elucidate the origins of freshwater fish in South Hainan by incorporating genetic data from DNA markers on both the mitochondrial cytochrome b gene (cyt b) and the nuclear recombination‐activating gene 1 (RAG‐1). Mitochondrial phylogenetic analysis identified two major lineages (lineages A and B), which may represent separate species. Divergence data suggested that C. gachua populations diverged between 0.516 and 2.376 myr. The divergence of the two cryptic species is congruent with sea‐level rise, which subsequently isolated Hainan from the mainland. During the Pleistocene glaciations, the entire region of the Gulf of Tonkin and the Qiongzhou Strait became part of the coastal plain of the Asian continent, which might have resulted in the current distribution patterns and dispersal routes of C. gachua populations. The formation of three sublineages in lineage A indicated that the Gulf of Tonkin was a geographical barrier between Hainan Island and mainland China but not between Vietnam and Hainan Island. The results of this study may help to elucidate the origins of freshwater fish in South Hainan and the phylogeographic structure of C. gachua.     

Deep History of East Asian Populations Revealed Through Genetic Analysis of the Ainu

Despite recent advances in population genomics, much remains to be elucidated with regard to East Asian population history. The Ainu, a hunter–gatherer population of northern Japan and Sakhalin island of Russia, are thought to be key to elucidating the prehistory of Japan and the peopling of East Asia. Here, we study the genetic relationship of the Ainu with other East Asian and Siberian populations outside the Japanese archipelago using genome-wide genotyping data. We find that the Ainu represent a deep branch of East Asian diversity more basal than all present-day East Asian farmers. However, we did not find a genetic connection between the Ainu and populations of the Tibetan plateau, rejecting their long-held hypothetical connection based on Y chromosome data. Unlike all other East Asian populations investigated, the Ainu have a closer genetic relationship with northeast Siberians than with central Siberians, suggesting ancient connections among populations around the Sea of Okhotsk. We also detect a recent genetic contribution of the Ainu to nearby populations, but no evidence for reciprocal recent gene flow is observed. Whole genome sequencing of contemporary and ancient Ainu individuals will be helpful to understand the details of the deep history of East Asians.     

Genetic diversify among Balkan trout populations based on RAPD analysis

Random amplified polymorphic DNA (RAPD) markers were used to estimate the population structure and phylogenetic relationships among samples of the Salmo trutta complex that inhabit the Balkan Peninsula. Five random oligodecamers were selected to amplify DNA from 140 fish from seven populations. Using these primers, 55 discernible DNA fragments were generated, of which 50 (90.91%) were polymorphic. The statistical results indicated that there was low genetic diversity within populations (with an average percentage of polymorphic bands (P) of 11.69% and a Nei’s genetic diversity index (h) of 0.035), but at the same time high genetic differentiation among populations (F _ST = 0.89). The distribution of genetic diversity among Balkan trout may result from their evolutionary history and reflects genetic drift coupled with bottleneck phenomena. Overall, RAPDs proved valuable tools for quick and reliable stock discrimination and provided information that might be useful regarding conservation and management of trout.     

Hybridization masks speciation in the evolutionary history of the Galápagos marine iguana

The effects of the direct interaction between hybridization and speciation—two major contrasting evolutionary processes—are poorly understood. We present here the evolutionary history of the Galápagos marine iguana (Amblyrhynchus cristatus) and reveal a case of incipient within-island speciation, which is paralleled by between-island hybridization. In-depth genome-wide analyses suggest that Amblyrhynchus diverged from its sister group, the Galápagos land iguanas, around 4.5 million years ago (Ma), but divergence among extant populations is exceedingly young (less than 50 000 years). Despite Amblyrhynchus appearing as a single long-branch species phylogenetically, we find strong population structure between islands, and one case of incipient speciation of sister lineages within the same island—ostensibly initiated by volcanic events. Hybridization between both lineages is exceedingly rare, yet frequent hybridization with migrants from nearby islands is evident. The contemporary snapshot provided by highly variable markers indicates that speciation events may have occurred throughout the evolutionary history of marine iguanas, though these events are not visible in the deeper phylogenetic trees. We hypothesize that the observed interplay of speciation and hybridization might be a mechanism by which local adaptations, generated by incipient speciation, can be absorbed into a common gene pool, thereby enhancing the evolutionary potential of the species as a whole.     

Autosomal and mtDNA Markers Affirm the Distinctiveness of Lions in West and Central Africa

The evolutionary history of a species is key for understanding the taxonomy and for the design of effective management strategies for species conservation. The knowledge about the phylogenetic position of the lion (Panthera leo) in West/Central Africa is largely based on mitochondrial markers. Previous studies using mtDNA only have shown this region to hold a distinct evolutionary lineage. In addition, anthropogenic factors have led to a strong decline in West/Central African lion numbers, thus, the conservation value of these populations is particularly high. Here, we investigate whether autosomal markers are concordant with previously described phylogeographic patterns, and confirm the unique position of the West/Central African lion. Analysis of 20 microsatellites and 1,454 bp of the mitochondrial DNA in 16 lion populations representing the entire geographic range of the species found congruence in both types of markers, identifying four clusters: 1) West/Central Africa, 2) East Africa, 3) Southern Africa and 4) India. This is not in line with the current taxonomy, as defined by the IUCN, which only recognizes an African and an Asiatic subspecies. There are no indications that genetic diversity in West/Central Africa lions is lower than in either East or Southern Africa, however, given this genetic distinction and the recent declines of lion numbers in this region, we strongly recommend prioritization of conservation projects in West/Central Africa. As the current taxonomic nomenclature does not reflect the evolutionary history of the lion, we suggest that a taxonomic revision of the lion is warranted.     

Genetic diversity analysis of Perinereis aibuhitensis based on ISSR and SRAP markers of Chinese coast populations

The objective of this study was to obtain an overview of the genetic relationships within Perinereis aibuhitensis using Inter-Simple Sequence Repeat (ISSR) and Sequence-Related Amplified Polymorphism (SRAP) markers that were derived from related populations residing in the Chinese coasts. The percentage of polymorphic bands, Nei's gene diversity and Shannon's information index revealed a high level of genetic diversity at the species level. The analysis of molecular variance revealed that 81.22% (ISSR) and 76.29% (SRAP) of variability were partitioned among individuals within populations, which indicated the coherent trend by Nei's genetic differentiation (Gst) (0.2568/0.2876). The gene flow number (Nm) was 1.4470/1.2385, which indicated that there was limited gene exchange between populations. The phylogenetic tree of the ten P. aibuhitensis populations was separated into four major clusters using the neighbor-joining (NJ) method. These results provide a simple and useful basis for P. aibuhitensis germplasm research and aquaculture breeding.     

遗传学视角下东亚人群的起源和演化

东亚是研究解剖学意义上现代人迁徙和演化的重要地带之一,该地区现代人群的起源及形成问题一直都是人类学领域广泛关注的焦点。遗传学研究为重建东亚人群历史提供了新的视角和见解。越来越多的遗传学证据表明,现代人约20万年前起源于非洲的晚期智人,并于10万年前走出非洲,大约在5~6万年前沿海岸线快速到达东亚南部,进而扩散到整个东亚地区。早期智人可能对走出非洲的现代人有一定程度的遗传贡献。早期定居、文化同化、人群迁徙以及基因交流等,对东亚人群的起源和演化起着至关重要的作用。前期的研究对东亚人群的源流历史进行了细致的分析,很大程度上解决了考古学、历史学等领域长期以来存在的分歧,然而这还需通过全基因组学和古DNA研究的进一步验证。本文从遗传学视角梳理和总结了东亚人群起源、迁徙和演化的历史,完善了对东亚人群演变的系统认识,并对未来东亚人群源流历史研究的发展方向做了展望。     

Phylogenetic and molecular dating analysis of Taiwan Blue Pheasant (Lophura swinhoii)

The Swinhoe's Pheasant (Lophura swinhoii) is an endemic and most endangered species to Taiwan, China. It belongs to the genus Lophura, family Phasianidae. To further investigate the evolutionary history of L. swinhoii, we determined its complete mitochondrial genome and reconstructed a single, robust phylogenetic tree. Our results showed that L. swinhoii is clustered with Lophura nycthemera and forms a sister group of Lophura ignita. The genus Lophura is strongly supported as the sister taxon of the genus Crossoptilon. The molecular clock analysis showed that the genetic divergence of L. swinhoii occurred in 2.71 (1.31–4.22) Mya. The most common ancestor of L. swinhoii might have migrated from mainland of South East Asia to Taiwan Island by the land bridge at 2.71 Mya ago. Taiwan Island is separated from the mainland by the sea (Taiwan Strait) and formed a separate island at around 2.5 Mya because of the transgression and regression. Therefore, geographical isolation and climate change may accelerate the evolution of L. swinhoii. In this study, we propose a biogeographic hypothesis for speciation of the L. swinhoii based on known events of the geographic and geological history of South East Asia and southeast China, which would benefit the understanding of evolutionary history of L. swinhoii as well as other galliform birds.