Cycles of glacial expansion and contraction throughout the Pleistocene drove increases and decreases, respectively, in the geographical range and population size of many animal species. Genetic data have revealed that during glacial maxima the distribution of many Eurasian animals was restricted to small refugial areas, from which species expanded to reoccupy parts of their former range as the climate warmed. It has been suggested that the extinct eastern moa (Emeus crassus)—a large, flightless bird from New Zealand—behaved analogously during glacial maxima, possibly surviving only in a restricted area of lowland habitat in the southern South Island of New Zealand during the Last Glacial Maximum (LGM). However, previous studies have lacked the power and geographical sampling to explicitly test this hypothesis using genetic data. Here we analyse 46 ancient mitochondrial genomes from Late Pleistocene and Holocene bones of the eastern moa from across their post-LGM distribution. Our results are consistent with a post-LGM increase in the population size and genetic diversity of eastern moa. We also demonstrate that genetic diversity was higher in eastern moa from the southern extent of their range, supporting the hypothesis that they expanded from a single glacial refugium following the LGM.
The olfactory receptor (OR) gene family is comprised of hundreds of intact and disrupted genes in humans. The compositions and copy number variation (CNV) of disrupted and intact OR genes among individuals is expected to cause variation in olfactory perception. However, little is known about OR genetic variation in many human populations. In this study, we used targeted capture enrichment and massive parallel short-read sequencing methods to examine genetic variation of OR genes, as well as of neutral genome regions as references, for 69 anonymized unrelated Japanese individuals. The capture probes were designed for 398 intact OR genes in the human reference genome hg38, and 85 neutral references. Probes were also designed for four unannotated and 99 ‘nearly-intact’ (hg38-pseudo) OR genes in hg38 and 53 chimpanzee OR genes in the Pantro3.0 genome database with no orthologs in hg38. All the hg38 OR genes and one Pantro 3.0 OR gene were retrieved. The mean sequencing depth was significantly higher than that of the 1000 Genomes Project. A total of 30 OR genes from hg38-intact and hg38-pseudo categories were newly found to be segregating pseudogenes. One hg38-pseudo OR gene was intact in all individuals. CNV was detected in 63 OR genes. Tajima’s D analysis for OR genes and neutral references was consistent with balancing selection to maintain allelic differences in intact OR genes. These results demonstrate that the targeted capture by probes with diversity-oriented design is far more effective than a whole-genome approach to retrieve OR genes and achieve high-depth sequencing and thus to reveal polymorphisms for the OR multigene family. The composition of OR genes in the human reference genome hg38 does not necessarily represent those in many humans, implying higher perceptual variation than previously thought. The current study inspires further investigation with a similar approach at a global scale.
A species complex is an assemblage of closely related species with blurred boundaries, and from which species could arise from different speciation processes and/or a speciation continuum. Such a complex can provide an opportunity to investigate evolutionary mechanisms acting on speciation. The Chrysanthemum zawadskii species complex in China, a monophyletic group of Chrysanthemum, consists of seven species with considerable morphological variation, diverse habitats and different distribution patterns. Here, we used Hyb-Seq data to construct a well-resolved phylogeny of the C. zawadskii complex. Then, we performed comparative analyses of variation patterns in morphology, ecology and distribution to investigate the roles of geography and ecology in this complex’s diversification. Lastly, we implemented divergence time estimation, species distribution modelling and ancestral area reconstruction to trace the evolutionary history of this complex. We concluded that the C. zawadskii complex originated in the Qinling–Daba mountains during the early Pliocene and then spread west and northward along the mountain ranges to northern China. During this process, geographical and ecological factors imposing different influences resulted in the current diversification and distribution patterns of this species complex, which is composed of both well-diverged species and diverging lineages on the path of speciation.
Previous phylogenetic studies have demonstrated that the Manilkarinae are a monophyletic subtribe if Northia is excluded. The subtribe consists of four genera: Faucherea, Labourdonnaisia, Labramia and Manilkara. However, the same phylogenetic studies also raised taxonomic issues concerning unclear generic delimitations and unresolved relationships. The current study’s aims are: to resolve these taxonomic issues using a molecular phylogeny based on hundreds of nuclear markers sequenced from a representative sampling of taxa across the four genera; to find relevant morphological characters allowing the distinction of the clades retrieved with the phylogeny; and finally to understand the evolutionary history of the subtribe by conducting a divergence time estimation and ancestral state reconstructions. Our phylogeny shows a well-resolved backbone with four main lineages: the Labramia clade, the main clade of Manilkara, a clade in which all species of Labourdonnaisia and Faucherea are mixed, and a clade of three Pacific Manilkara species. The main clade of Manilkara is retrieved as sister to Labramia, and the Labourdonnaisia-Faucherea clade is clearly assessed as sister to the three Pacific Manilkara species. As a consequence, Faucherea is synonymized with Labourdonnaisia, and the three Pacific Manilkara are considered to be a separate genus, for which the name Abebaia is resurrected. We provide emended descriptions for Labourdonnaisia and Abebaia as well as the necessary new combinations. The ancestral state reconstruction of flower characters shows that ancestral Manilkarinae were characterized by a hexamerous corolla, well-developed dorsal appendages and staminodes, and a pubescent ovary. These character states have been retained in the main Manilkara clade, but surprisingly also in Abebaia, which appears as a cryptic genus. The lack of dorsal appendages and the reduction of staminodes observed in Labourdonnaisia appeared after the split from Abebaia. The increase in corolla merism observed mainly in the Mascarene Labourdonnaisia, which was used to separate it from Faucherea, appears to be a derived state, which evolved separately in a few species during the radiation of Labourdonnaisia on Madagascar and the Mascarenes. The glabrous ovary state observed in Labramia also constitutes a derived synapomorphic state in the genus.
Aim Phenotypes promoting dispersal over ecological timescales may have macroevolutionary consequences, such as long-distance dispersal and diversification. However, whether dispersal traits explain the distribution of pantropical plant groups remains unclear. Here we reconstruct the biogeographical history of a tree clade to assess whether seed dispersal traits and biome-switching explain the clade’s pantropical distribution. Location Pantropical. Taxon The Pterocarpus clade (Leguminosae/Fabaceae). Methods We sequenced 303 nuclear loci using target capture and generated a time-calibrated phylogenomic tree. We also generated a corroborative time-calibrated phylogenetic tree from data-mined Sanger-sequencing data. We then collated distribution data and seed dispersal morphology traits to compare trait-dependent and trait-independent biogeographical models, allowing us to infer whether dispersal traits influenced Pterocarpus’ spatio-temporal evolution. Finally, using the results of these model tests, we estimated the ancestral ranges and biomes of Pterocarpus species to better understand their biogeographical history, and assessed the degree and direction of biome-switching over the course of their diversification. Results We recovered well-supported phylogenetic relationships within Pterocarpus, within which there were two subclades – one neotropical and the other palaeotropical. Our divergence date estimates suggested that Pterocarpus diversified from around 12 Ma, during the Miocene. Trait-dependent biogeographical models were rejected for both range and biome evolution within Pterocarpus, but models including dispersal were supported. Pterocarpus’ ancestral node shared a range across the new-world and old-world tropics, followed by divergence into palaeotropical and neotropical clades. Biome-switching occurred most frequently into rainforest and grassland. Main conclusions Our analyses suggest that Pterocarpus underwent infrequent cross-continental dispersal and establishment into novel biomes. While this was minimally impacted by seed dispersal traits, biome-switching following long-distance dispersal and climate change have played an important role in diversification within Pterocarpus since the Miocene. Indeed, rare events of long-distance dispersal likely explain the wide distributions of many pantropical plant species.
Recent advances in phylogenomics allow for the use of large amounts of genetic information in phylogenetic inference. Ideally, the increased resolution and accuracy of such inferences facilitate improved understanding of macroevolutionary processes. Here, we integrate ultraconserved elements (UCEs) with fossil and biogeographic range data to explore diversification and geographic range evolution in the diverse turtle ant genus Cephalotes Latreille, 1802 (Hymenoptera: Formicidae). We focus on the potential role of the uplift of the Panamanian land bridge and the putative ephemeral GAARlandia land bridge linking South America and the Antilles in shaping evolution in this group. Our phylogenetic analyses provide new resolution to the backbone of the turtle ant phylogeny. We further found that most geographic range shifts between South America and Central America regions were temporally consistent with the development of the Panamanian land bridge, while we did not find support for the GAARlandia land bridge. Additionally, we did not infer any shifts in diversification rates associated with our focal land bridges, or any other historical events (we inferred a single diversification rate regime across the genus). Our findings highlight the impact of the Panamanian land bridge for Cephalotes geographic range evolution as well as the influence of taxonomic sampling on macroevolutionary inferences.
Using genetic, morphological, and geographical evidence, we investigate the species-level taxonomy and evolutionary history of the Pseudomyrmex elongatulus group, a clade of ants distributed from southwestern United States to Costa Rica. Through targeted enrichment of 2,524 UCE (ultraconserved element) loci we generate a phylogenomic data set and clarify the phylogenetic relationships and biogeographic history of these ants. The crown group is estimated to have originated ~8 Ma, in Mexico and/or northern Central America, and subsequently expanded into southern Central America and the southwestern Nearctic. The P. elongatulus group contains a mix of low- and high-elevation species, and there were apparently multiple transitions between these habitat types. We uncover three examples of one species—of restricted or marginal geographical distribution—being embedded phylogenetically in another species, rendering the latter paraphyletic. One of these cases involves an apparent workerless social parasite that occurs sympatrically with its parent species, with the latter serving as host. This suggests a sympatric origin of the parasite species within the distribution range of its host. Species boundaries are tested using three molecular delimitation approaches (SODA, bPTP, BPP) but these methods generate inflated species estimates (26–46 species), evidently because of a failure to distinguish population structure from species differences. In a formal taxonomic revision of the P. elongatulus group, based on almost 3,000 specimens from ~625 localities, we allow for geographic variation within species and we employ distinctness-in-sympatry criteria for testing hypotheses about species limits. Under these guidelines we recognize 13 species, of which nine are new: P. arcanus, sp. nov. (western Mexico); P. capillatus, sp. nov. (western Mexico); P. cognatus, sp. nov. (Chiapas, Mexico to Nicaragua); P. comitator, sp. nov. (Chiapas, Mexico); P. ereptor, sp. nov. (Veracruz, Mexico); P. exoratus, sp. nov. (southeastern Mexico, Honduras); P. fasciatus, sp. nov. (Chiapas, Mexico to Costa Rica); P. nimbus, sp. nov. (Costa Rica); and P. veracruzensis, sp. nov. (Veracruz, Mexico). Our study highlights the value of combining phylogenomic, phenotypic, and geographical data to resolve taxonomic and evolutionary questions.
Family Cortinariaceae currently includes only one genus, Cortinarius, which is the largest Agaricales genus, with thousands of species worldwide. The species are important ectomycorrhizal fungi and form associations with many vascular plant genera from tropicals to arctic regions. Genus Cortinarius contains a lot of morphological variation, and its complexity has led many taxonomists to specialize in particular on infrageneric groups. The previous attempts to divide Cortinarius have been shown to be unnatural and the phylogenetic studies done to date have not been able to resolve the higher-level classification of the group above section level. Genomic approaches have revolutionized our view on fungal relationships and provide a way to tackle difficult groups. We used both targeted capture sequencing and shallow whole genome sequencing to produce data and to perform phylogenomic analyses of 75 single-copy genes from 19 species. In addition, a wider 5-locus analysis of 245 species, from the Northern and Southern Hemispheres, was also done. Based on our results, a classification of the family Cortinariaceae into ten genera—Cortinarius, Phlegmacium, Thaxterogaster, Calonarius, Aureonarius, Cystinarius, Volvanarius, Hygronarius, Mystinarius, and Austrocortinarius—is proposed. Seven genera, 10 subgenera, and four sections are described as new to science and five subgenera are introduced as new combinations in a new rank. In addition, 41 section names and 514 species names are combined in new genera and four lecto- and epitypes designated. The position of Stephanopus in suborder Agaricineae remains to be studied. Targeted capture sequencing is used for the first time in fungal taxonomy in Basidiomycetes. It provides a cost-efficient way to produce -omics data in species-rich groups. The -omics data was produced from fungarium specimens up to 21 years old, demonstrating the value of museum specimens in the study of the fungal tree of life. This study is the first family revision in Agaricales based on genomics data and hopefully many others will soon follow.
The identity of the mummified Lady from the Barfüsser Church in Basel, Switzerland has been unsolved for decades, despite the prominent location of the burial place in front of the choir screen. A recent multidisciplinary research approach came up with a possible candidate, Anna Catharina Bischoff who died in Basel in 1787 with an age of 69 years (1719–1787). To verify the identity of the mummy, genealogists of the Citizen Science Basel discovered three living individuals of the maternal lineage of two different family branches, separated from Anna Catharina Bischoff by up to 22 generations. In this study we compare the ancient mitochondrial DNA of the mummy recovered from a premolar to the mitochondrial DNA of these three candidates. Initially the mitochondrial hypervariable regions I and II of the living individuals were screened using the Sanger sequencing method. This was followed by a mitochondrial capture approach and next generation sequencing to enrich for the whole mitochondrial genome of the mummy and one living person. A full mitochondrial genome has been recovered of both individuals sharing an identical haplotype. The sequence was assigned to the mitochondrial haplogroup U5a1+!16192 including two private mutations 10006G and 16293C. Only by using an interdisciplinary approach combining ancient DNA analysis and genealogy a maternal lineage of a non-noble family spanning 22 generations could be confirmed.
Ann Arbor, MI 48103
(d/b/a Daicel Arbor Biosciences)
All Rights Reserved.