Effects of monsoon on distribution patterns of tropical plants in Asia

Comparing with other regions, Asia is mostly dominated by the monsoon climate and tropical plants can be found at the furthest places away from the equator. Understanding the role of monsoon in the dispersal and evolution of tropical plants is helpful for exploring the distribution patterns of vegetation and mechanisms underlying the origin and maintenance of biodiversity in Asia. In summer, there are three types of monsoon in Asia, i.e. East Asia Monsoon, South Asia Monsoon, North-west Pacific Ocean Monsoon. The summer monsoon climate in Asia originated at about 40 Ma, when the early angiosperm evolved and started its diversification in Southeast Asia and South China. It suggested that the monsoon may facilitate the quick speciation and spread of early angiosperm. Monsoon climate facilitates the northward spread of Asia’s tropical plants and some tropical plants can be found even at Yarlung Zangbo River and the boundaries of Guizhou-Guangxi-Yunnan. Such effetcs largely change distribution patterns of zonal vegetation and even causes local vegetation types in some places with unusual topography such as tropical seasonal rainforests, monsoon rainforests, savanna and grassland along dry-hot valley in Southwest China, coastal savanna in West Hainan Island. The three summer monsoons interact at Southwest China and Indo-China Peninsula and these regions are dominated by limestone landscapes and high mountains with big rivers. Some Asia-endemic tropical taxa even formed a diversification and endemism center at this region, which may be a reason for the formation and maintenance of Indo-Burma biodiversity hotspots with global warming, the monsoon may further promote the northward spread of tropical plants and may have fundamental effects on biodiversity and flora evolution in South China.     

Fruits of Firmiana and Craigia (Malvaceae) from the Eocene of the Central Tibetan Plateau with emphasis on biogeographic history

The fossil record evidences an old origin and diversification of Malvaceae in the Northern Hemisphere. The central Tibetan Plateau was at a low elevation with a monsoon influence during the Eocene, allowing the development of a subtropical flora containing Malvaceae. The taxonomic study of fossils from the Eocene of what is now the Tibetan Plateau is still ongoing. Malvaceae fossils from the Eocene Jianglang flora, are attributed to sub-families Tilioideae and Sterculioideae, and are compared with modern species. A new specimen of Firmiana is described based on a fruit valve with a pinnate venation, the secondary veins starting at the ventral suture and reaching the midvein, and the seeds attached at the proximal part of the ventral suture. This specimen represents the earliest known occurrence of the genus. A new occurrence of Craigia is also reported based on detached membranous valves of a fruit capsule with a prominent fusiform locular area and radiating venation. Based on the fossil record of Firmiana and its modern distribution, we infer that the genus may have originated in East Asia and subsequently diversified in South China and Southeast Asia. The new occurrence of Craigia indicates that the genus was distributed in humid areas in South, Southwest and North China during the Eocene. Both fossil records evidence the important role that the Tibetan region played in the diversification of plants in East and Southeast Asia.     

Reticulate evolution and sea‐level fluctuations together drove species diversification of slipper orchids (Paphiopedilum) in South‐East Asia

South‐East Asia covers four of the world's biodiversity hotspots, showing high species diversity and endemism. Owing to the successive expansion and contraction of distribution and the fragmentation by geographical barriers, the tropical flora greatly diversified in this region during the Tertiary, but the evolutionary tempo and mode of species diversity remain poorly investigated. Paphiopedilum, the largest genus of slipper orchids comprising nearly 100 species, is mainly distributed in South‐East Asia, providing an ideal system for exploring how plant species diversity was shaped in this region. Here, we investigated the evolutionary history of this genus with eight cpDNA regions and four low‐copy nuclear genes. Discordance between gene trees and network analysis indicates that reticulate evolution occurred in the genus. Ancestral area reconstruction suggests that vicariance and long‐distance dispersal together led to its current distribution. Diversification rate variation was detected and strongly correlated with the species diversity in subg. Paphiopedilum (~80 species). The shift of speciation rate in subg. Paphiopedilum was coincident with sea‐level fluctuations in the late Cenozoic, which could have provided ecological opportunities for speciation and created bridges or barriers for gene flow. Moreover, some other factors (e.g. sympatric distribution, incomplete reproductive barriers and clonal propagation) might also be advantageous for the formation and reproduction of hybrid species. In conclusion, our study suggests that the interplay of reticulate evolution and sea‐level fluctuations has promoted the diversification of the genus Paphiopedilum and sheds light into the evolution of Orchidaceae and the historical processes of plant species diversification in South‐East Asia.     

Both temperature fluctuations and East Asian monsoons have driven plant diversification in the karst ecosystems from southern China

Karst ecosystems in southern China are species‐rich and have high levels of endemism, yet little is known regarding the evolutionary processes responsible for the origin and diversification of karst biodiversity. The genus Primulina (Gesneriaceae) comprises ca. 170 species endemic to southern China with high levels of ecological (edaphic) specialization, providing an exceptional model to study the plant diversification in karsts. We used molecular data from nine chloroplast and 11 nuclear regions and macroevolutionary analyses to assess the origin and cause of species diversification due to palaeoenvironmental changes and edaphic specialization in Primulina. We found that speciation was positively associated with changes in past temperatures and East Asian monsoons through the evolutionary history of Primulina. Climatic change around the mid‐Miocene triggered an early burst followed by a slowdown of diversification rate towards the present with the climate cooling. We detected different speciation rates among edaphic types, and transitions among soil types were infrequently and did not impact the overall speciation rate. Our findings suggest that both global temperature changes and East Asian monsoons have played crucial roles in floristic diversification within the karst ecosystems in southern China, such that speciation was higher when climate was warmer and wetter. This is the first study to directly demonstrate that past monsoon activity is positively correlated with speciation rate in East Asia. This case study could motivate further investigations to assess the impacts of past environmental changes on the origin and diversification of biodiversity in global karst ecosystems, most of which are under threat.     

面向生态系统结构的生物多样性保护成效空间对比评估

开展生物多样性保护成效对比评估对于合理执行生态补偿机制的转移支付政策,以及进一步促进全国生态保护管理水平的有效提升都具有重要意义。以2015年版《全国生态功能区划》划定的生物多样性保护重要生态功能区为研究对象,采用生物多样性保护成效结构指数,探讨重要生态功能区生物多样性保护成效的区域分异情况。研究结果表明：(1)华南、华东与华中地区重要生态功能区的生态结构参照基准较高,东北地区重要生态功能区居中,较差的重要生态功能区则位于西南和西北地区,说明了全国生态环境本底的区域分异性;(2)西北和西南地区重要生态功能区的保护成效结构指数较高,华中和华南地区居中,而东北和华东地区的保护成效结构指数较低,体现了2015年全国重要生态功能区生物多样性保护成效的空间差异情况;(3)从草原、森林与湿地生物多样性的保护成效结构指数来看,西北与西南地区、东北和西南地区及华东地区的重要生态功能区分别具有较大优势。上述研究结果反映了全国重要生态功能区生物多样性保护成效优劣的空间差异状况,可为政府部门健全生态补偿机制以及制定生态系统恢复方案提供决策参考。     

Phylogenomics of pike cichlids (Cichlidae: Crenicichla): the rapid ecological speciation of an incipient species flock

The rapid rise of phenotypic and ecological diversity in independent lake‐dwelling groups of cichlids is emblematic of the East African Great Lakes. In this study, we show that similar ecologically based diversification has occurred in pike cichlids (Crenicichla) throughout the Uruguay River drainage of South America. We collected genomic data from nearly 500 ultraconserved element (UCEs) loci and >260 000 base pairs across 33 species, to obtain a phylogenetic hypothesis for the major species groups and to evaluate the relationships and genetic structure among five closely related, endemic, co‐occurring species (the Uruguay River species flock; URSF). Additionally, we evaluated ecological divergence of the URSF based on body and lower pharyngeal jaw (LPJ) shape and gut contents. Across the genus, we recovered novel relationships among the species groups. We found strong support for the monophyly of the URSF; however, relationships among these species remain problematic, likely because of the rapid and recent evolution of this clade. Clustered co‐ancestry analysis recovered most species as well delimited genetic groups. The URSF species exhibit species‐specific body and LPJ shapes associated with specialized trophic roles. Collectively, our results suggest that the URSF consists of incipient species that arose via ecological speciation associated with the exploration of novel trophic roles.     

Phylogeny of spiny frogs Nanorana (Anura: Dicroglossidae) supports a Tibetan origin of a Himalayan species group

Recent advances in the understanding of the evolution of the Asian continent challenge the long‐held belief of a faunal immigration into the Himalaya. Spiny frogs of the genus Nanorana are a characteristic faunal group of the Himalaya–Tibet orogen (HTO). We examine the phylogeny of these frogs to explore alternative biogeographic scenarios for their origin in the Greater Himalaya, namely, immigration, South Tibetan origin, strict vicariance. We sequenced 150 Nanorana samples from 62 localities for three mitochondrial (1,524 bp) and three nuclear markers (2,043 bp) and complemented the data with sequence data available from GenBank. We reconstructed a gene tree, phylogenetic networks, and ancestral areas. Based on the nuDNA, we also generated a time‐calibrated species tree. The results revealed two major clades (Nanorana and Quasipaa), which originated in the Lower Miocene from eastern China and subsequently spread into the HTO (Nanorana). Five well‐supported subclades are found within Nanorana: from the East, Central, and Northwest Himalaya, the Tibetan Plateau, and the southeastern Plateau margin. The latter subclade represents the most basal group (subgenus Chaparana), the Plateau group (Nanorana) represents the sister clade to all species of the Greater Himalaya (Paa). We found no evidence for an east–west range expansion of Paa along the Himalaya, nor clear support for a strict vicariance model. Diversification in each of the three Himalayan subclades has probably occurred in distinct areas. Specimens from the NW Himalaya are placed basally relative to the highly diverse Central Himalayan group, while the lineage from the Tibetan Plateau is placed within a more terminal clade. Our data indicate a Tibetan origin of Himalayan Nanorana and support a previous hypothesis, which implies that a significant part of the Himalayan biodiversity results from primary diversification of the species groups in South Tibet before this part of the HTO was uplifted to its recent heights.     

The diversification of Halenia (Gentianaceae): ecological opportunity versus key innovation

The plant genus Halenia (Gentianaceae) consists of herbs growing in temperate and tropical alpine habitats and most species possess flowers in which nectar is produced in spurs. This probably helps reward only specialized long-tongued pollinators, and a narrow pollinator/flower relationship is thought to accelerate diversification rates (a key innovation). To test the pattern of diversification of Halenia against the unspurred sister group we reconstructed phylogenetic relationships among 22 species plus outgroups using nuclear ITS and chloroplast rpl16 intron sequence data. We show that Halenia originated in East Asia and migrated via North America into Central America. From there, it colonized South America three times independently, probably within the last million years. Significant changes in diversification rates were found during the evolution of Halenia using a sister group method, a likelihood method, and a diversity-through-time plot. In contrast to other studies, we could not observe a direct speciation rate effect of the evolution of nectar spurs in comparison with the unspurred sister group of Halenia. Rather, increases in diversification occurred following the colonization of Central and South America by spurred progenitor taxa. This later switch in diversification may have resulted from the availability of new geographical and ecological opportunities, or from the availability of more and different pollinators in these regions. Following the latter hypothesis, the nectar spurs were a preadaption and functioned as a key innovation only in this new biotic environment. After an initial rapid increase, a reduction in diversification rate was observed in Central America, probably illustrating density dependence of speciation rates. Finally, we found preliminary evidence for the key innovation hypothesis in geologically young spurred and unspurred lineages of Halenia in South America.     

POSTFIRE RESPONSE AND GENETIC DIVERSITY IN ERICA COCCINEA: CONNECTING POPULATION DYNAMICS AND DIVERSIFICATION IN A BIODIVERSITY HOTSPOT

Understanding the processes of biological diversification is a central topic in evolutionary biology. The South African Cape fynbos, one of the major plant biodiversity hotspots out of the tropics, has prompted several hypotheses about the causes of generation and maintenance of biodiversity. Fire has been traditionally invoked as a key element to explain high levels of biodiversity in highly speciose fynbos taxa, such as the genus Erica. In this study, we have implemented a microevolutionary approach to elucidate how plant‐response to fire may contribute to explain high levels of diversification in Erica. By using microsatellite markers, we investigated the genetic background of seeder (fire‐sensitive) and resprouter (fire‐resistant) populations of the fynbos species Erica coccinea. We found higher within‐population genetic diversity and higher among‐population differentiation in seeder populations and interpreted these higher levels of genetic diversification as a consequence of the comparatively shorter generation times and faster population turnover in the seeder form of this species. Considering that genetic divergence among populations may be seen as the initial step to speciation, the parallelism between these results and the pattern of biodiversity at the genus level offers stimulating insights into understanding causes of speciation of the genus Erica in the Cape fynbos.     

A rapid diversification of rainforest trees (Guatteria; Annonaceae) following dispersal from Central into South America

Several recent studies have suggested that a substantial portion of today's plant diversity in the Neotropics has resulted from the dispersal of taxa into that region rather than vicariance, but more data are needed to substantiate this claim. Guatteria (Annonaceae) is, with 265 species, the third largest genus of Neotropical trees after Inga (Fabaceae) and Ocotea (Lauraceae), and its widespread distribution and frequent occurrence makes the genus an excellent model taxon to study diversification patterns. This study reconstructed the phylogeny of Guatteria and inferred three major biogeographical events in the history of the genus: (1) a trans-oceanic Miocene migration from Central into South America before the closing of the Isthmus of Panama; (2) a major diversification of the lineage within South America; and (3) several migrations of South American lineages back into Central America via the closed Panamanian land bridge. Therefore, Guatteria is not an Amazonian centred-genus sensu Gentry but a major Miocene diversification that followed its dispersal into South America. This study provides further evidence that migration into the Neotropics was an important factor in the historical assembly of its biodiversity. Furthermore, it is shown that phylogenetic patterns are comparable to those found in Ocotea and Inga and that a closer comparison of these genera is desirable.     

A dated phylogeny of Lardizabalaceae reveals an unusual long-distance dispersal across the Pacific Ocean and the rapid rise of East Asian subtropical evergreen broadleaved forests in the late Miocene

Temperate South American–Asian disjunct distributions are the most unusual in organisms, and challenging to explain. Here, we address the origin of this unusual disjunction in Lardizabalaceae using explicit models and molecular data. The family (c.40 species distributed in ten genera) also provides an opportunity to explore the historical assembly of East Asian subtropical evergreen broadleaved forests, a typical and luxuriant vegetation in East Asia. DNA sequences of five plastid loci of 42 accessions representing 23 species of Lardizabalaceae (c. 57.5% of estimated species diversity), and 19 species from the six other families of Ranunculales, were used to perform phylogenetic analyses. By dating the branching events and reconstructing ancestral ranges, we infer that extant Lardizabalaceae dated to the Upper Cretaceous of East Asia and that the temperate South American lineage might have split from its East Asian sister group at c. 24.4 Ma. A trans-Pacific dispersal possibly by birds from East Asia to South America is plausible to explain the establishment of the temperate South American–East Asian disjunction in Lardizabalaceae. Diversification rate analyses indicate that net diversification rates of Lardizabalaceae experienced a significant increase around c. 7.5 Ma. Our findings suggest that the rapid rise of East Asian subtropical evergreen broadleaved forests occurred in the late Miocene, associated with the uplift of the Tibetan Plateau and the intensified East Asian monsoon, as well as the higher winter temperature and atmospheric CO₂ levels.     

Diversification patterns in the CES clade (Brassicaceae tribes Cremolobeae,Eudemeae, Schizopetaleae) in Andean South America

Dated molecular phylogenetic trees show that the Andean uplift had a major impact on South American biodiversity. For many Andean groups, accelerated diversification (radiation) has been documented. However, not all Andean lineages appear to have diversified following the model of rapid radiation, particularly in the central and southern Andes. Here, we investigated the diversification patterns for the largest South American‐endemic lineage of Brassicaceae, composed of tribes Cremolobeae, Eudemeae and Schizopetaleae (CES clade). Species of this group inhabit nearly all Andean biomes and adjacent areas including the Atacama–Sechura desert, the Chilean Matorral and the Patagonian Steppe. First, we studied diversification times and historical biogeography of the CES clade. Second, we analysed diversification rates through time, lineages and associated life forms. Results demonstrate that early diversification of the CES clade occurred in the early to mid‐Miocene (c. 12–19 Mya) and involved the central Andes, the southern Andes and the Patagonian Steppe, and the Atacama–Sechura desert. The Chilean Matorral and northern Andes were colonized subsequently in the early Pliocene (4–5 Mya). Diversification of the CES clade was recovered as a gradual process without any evidence for rate shifts or rapid radiation, in contrast to many other Andean groups analysed so far. Diversification time/rates and biogeographical patterns obtained for the CES clade are discussed and compared with patterns and conclusions reported for other Andean plant lineages.     

Spatiotemporal maintenance of flora in the Himalaya biodiversity hotspot: Current knowledge and future perspectives

Mountain ecosystems support a significant one‐third of all terrestrial biodiversity, but our understanding of the spatiotemporal maintenance of this high biodiversity remains poor, or at best controversial. The Himalaya hosts a complex mountain ecosystem with high topographic and climatic heterogeneity and harbors one of the world''s richest floras. The high species endemism, together with increasing anthropogenic threats, has qualified the Himalaya as one of the most significant global biodiversity hotspots. The topographic and climatic complexity of the Himalaya makes it an ideal natural laboratory for studying the mechanisms of floral exchange, diversification, and spatiotemporal distributions. Here, we review literature pertaining to the Himalaya in order to generate a concise synthesis of the origin, distribution, and climate change responses of the Himalayan flora. We found that the Himalaya supports a rich biodiversity and that the Hengduan Mountains supplied the majority of the Himalayan floral elements, which subsequently diversified from the late Miocene onward, to create today''s relatively high endemicity in the Himalaya. Further, we uncover links between this Miocene diversification and the joint effect of geological and climatic upheavals in the Himalaya. There is marked variance regarding species dispersal, elevational gradients, and impact of climate change among plant species in the Himalaya, and our review highlights some of the general trends and recent advances on these aspects. Finally, we provide some recommendations for conservation planning and future research. Our work could be useful in guiding future research in this important ecosystem and will also provide new insights into the maintenance mechanisms underpinning other mountain systems.     

Environmental niche conservatism explains the accumulation of species richness in Mediterranean‐hotspot plant genera

The causes of exceptionally high plant diversity in Mediterranean‐climate biodiversity hotspots are not fully understood. We asked whether a mechanism similar to the tropical niche conservatism hypothesis could explain the diversity of four large genera (Protea, Moraea, Banksia, and Hakea) with distributions within and adjacent to the Greater Cape Floristic Region (South Africa) or the Southwest Floristic Region (Australia). Using phylogenetic and spatial data we estimated the environmental niche of each species, and reconstructed the mode and dynamics of niche evolution, and the geographic history, of each genus. For three genera, there were strong positive relationships between the diversity of clades within a region and their inferred length of occupation of that region. Within genera, there was evidence for strong evolutionary constraint on niche axes associated with climatic seasonality and aridity, with different niche optima for hotspot and nonhotspot clades. Evolutionary transitions away from hotspots were associated with increases in niche breadth and elevated rates of niche evolution. Our results point to a process of “hotspot niche conservatism” whereby the accumulation of plant diversity in Mediterranean‐type ecosystems results from longer time for speciation, with dispersal away from hotspots limited by narrow and phylogenetically conserved environmental niches.     

木兰科（Magnoliaceae）的起源、进化和地理分布

木兰科为亚洲－美洲间断分布科,全世界有１５属,２４６种,主要分布于亚洲东南部的热带、亚热带地区,从喜马拉雅至日本,向南达新几内亚及新不列颠;少数种类分布于北美东南部、中美至南美巴西．中国有１１属,约９９种．木兰科的现代分布中心在东亚－东南亚地区．根据木兰科的化石记录、系统发育和现代分布,推测其起源时间为早白垩纪,甚至更早．起源地可能在中国的西南地区,并由此向外辐射,向东经日本、俄罗斯远东地区经白令陆桥进入北美;向西经西亚、欧洲,通过格陵兰进入北美,然后到达南美;向南经印度支那、马来西亚,直至新几内亚．东亚－北美间断分布的形成是受第四纪冰期的影响;南美的木兰科是从北美迁移而来．     

木兰科（Magnoliaceae）的起源、进化和地理分布

木兰科为亚洲－美洲间断分布科,全世界有１５属,２４６种,主要分布于亚洲东南部的热带、亚热带地区,从喜马拉雅至日本,向南达新几内亚及新不列颠;少数种类分布于北美东南部、中美至南美巴西．中国有１１属,约９９种．木兰科的现代分布中心在东亚－东南亚地区．根据木兰科的化石记录、系统发育和现代分布,推测其起源时间为早白垩纪,甚至更早．起源地可能在中国的西南地区,并由此向外辐射,向东经日本、俄罗斯远东地区经白令陆桥进入北美;向西经西亚、欧洲,通过格陵兰进入北美,然后到达南美;向南经印度支那、马来西亚,直至新几内亚．东亚－北美间断分布的形成是受第四纪冰期的影响;南美的木兰科是从北美迁移而来．     

In and out of Madagascar: Dispersal to Peripheral Islands, Insular Speciation and Diversification of Indian Ocean Daisy Trees (Psiadia, Asteraceae)

Madagascar is surrounded by archipelagos varying widely in origin, age and structure. Although small and geologically young, these archipelagos have accumulated disproportionate numbers of unique lineages in comparison to Madagascar, highlighting the role of waif-dispersal and rapid in situ diversification processes in generating endemic biodiversity. We reconstruct the evolutionary and biogeographical history of the genus Psiadia (Asteraceae), a plant genus with near equal numbers of species in Madagascar and surrounding islands. Analyzing patterns and processes of diversification, we explain species accumulation on peripheral islands and aim to offer new insights on the origin and potential causes for diversification in the Madagascar and Indian Ocean Islands biodiversity hotspot. Our results provide support for an African origin of the group, with strong support for non-monophyly. Colonization of the Mascarenes took place by two evolutionary distinct lineages from Madagascar, via two independent dispersal events, each unique for their spatial and temporal properties. Significant shifts in diversification rate followed regional expansion, resulting in co-occurring and phenotypically convergent species on high-elevation volcanic slopes. Like other endemic island lineages, Psiadia have been highly successful in dispersing to and radiating on isolated oceanic islands, typified by high habitat diversity and dynamic ecosystems fuelled by continued geological activity. Results stress the important biogeographical role for Rodrigues in serving as an outlying stepping stone from which regional colonization took place. We discuss how isolated volcanic islands contribute to regional diversity by generating substantial numbers of endemic species on short temporal scales. Factors pertaining to the mode and tempo of archipelago formation and its geographical isolation strongly govern evolutionary pathways available for species diversification, and the potential for successful diversification of dispersed lineages, therefore, appears highly dependent on the timing of arrival, as habitat and resource properties change dramatically over the course of oceanic island evolution.     

Long‐term isolation and stability explain high genetic diversity in the Eastern Himalaya

China's Southwest Mountainous Region in Eastern Himalaya is a ‘biodiversity hotspot’ of global interest for conservation. Yet little is known about what has driven this unique diversity. The dramatic topography of the Southwest Mountainous Region resulting from the tectonic uplift during the late Pliocene leads to dramatic ecological stratification, which creates physical barriers to migration and isolates organisms into different subregions and mountain systems. This agrees with the observation that the phylogeographical patterns found in four species of birds (Alcippe morrisonia, Stachyridopsis ruficeps, Parus monticolus and Aegithalos concinnus) distributed in this region are characterized by deep splits between lineages that coalesce between 0.8 and 2.1 Ma. Unlike other regions at this latitude, the Southwest Mountainous Region was largely unaffected by the Pleistocene glaciations. Genetically isolated populations of these birds could thus be maintained throughout the Pleistocene in these rather stable montane environments. In comparison, we found radically different phylogeographical patterns in populations of the same four species distributed in the adjacent lowland, the Central China region. This region has a distinctly different geological history with dramatic, climate‐induced shifts in vegetation during the Pleistocene. Here, we found a considerably less geographical structure in the genetic variation and a much younger coalescence time (0.3–0.7 Ma). We also found evidence of genetic bottlenecks during the glacial periods and gene flow during the interglacial expansions. We conclude that the high genetic diversity in the Southwest Mountainous Region results from a long‐term in situ diversification within these evolutionary isolated and environment stable montane habitats.     

The Great American Interchange in birds: a phylogenetic perspective with the genus Trogon

The 'Great American Interchange' (GAI) is recognized as having had a dramatic effect on biodiversity throughout the Neotropics. However, investigation of patterns in Neotropical avian biodiversity has generally been focused on South American taxa in the Amazon Basin, leaving the contribution of Central American taxa under-studied. More rigorous studies of lineages distributed across the entire Neotropics are needed to uncover phylogeographical patterns throughout the area, offering insights into mechanisms that contribute to overall Neotropical biodiversity. Here we use mitochondrial DNA sequence data and intensive geographical sampling from the widespread Neotropical avian genus Trogon to investigate the role of the GAI in shaping its phylogeographical history. Our results show that genetic diversity in Trogon exceeds the perceived biodiversity, and that the GAI resulted in lineage diversification within the genus. Despite greater diversity in South America, a Central American centre of origin with multiple and independent dispersals into South America is indicated. These dispersals were followed by the evolution of divergent lineages associated with the Andes Mountains and other South American geographical features. According to our phylogenetic reconstructions, several species, which were originally defined by morphological characters, are nonmonophyletic. In sum, our results elucidate the evolutionary history of Trogon , reveal patterns obscured by extant biodiversity, and serve as a biogeographical model to consider in future studies.     

Genetic Relationships of Ethnic Minorities in Southwest China Revealed by Microsatellite Markers

Population migrations in Southwest and South China have played an important role in the formation of East Asian populations and led to a high degree of cultural diversity among ethnic minorities living in these areas. To explore the genetic relationships of these ethnic minorities, we systematically surveyed the variation of 10 autosomal STR markers of 1,538 individuals from 30 populations of 25 ethnic minorities, of which the majority were chosen from Southwest China, especially Yunnan Province. With genotyped data of the markers, we constructed phylogenies of these populations with both D_A and D_C measures and performed a principal component analysis, as well as a clustering analysis by structure. Results showed that we successfully recovered the genetic structure of analyzed populations formed by historical migrations. Aggregation patterns of these populations accord well with their linguistic affiliations, suggesting that deciphering of genetic relationships does in fact offer clues for study of ethnic differentiation.