Current global patterns of biodiversity result from processes that operate over both space and time and thus require an integrated macroecological and macroevolutionary perspective. Molecular time trees have advanced our understanding of the tempo and mode of diversification and have identified remarkable adaptive radiations across the tree of life. However, incomplete joint phylogenetic and geographic sampling has limited broad-scale inference. Thus, the relative prevalence of rapid radiations and the importance of their geographic settings in shaping global biodiversity patterns remain unclear. Here we present, analyse and map the first complete dated phylogeny of all 9,993 extant species of birds, a widely studied group showing many unique adaptations. We find that birds have undergone a strong increase in diversification rate from about 50 million years ago to the near present. This acceleration is due to a number of significant rate increases, both within songbirds and within other young and mostly temperate radiations including the waterfowl, gulls and woodpeckers. Importantly, species characterized with very high past diversification rates are interspersed throughout the avian tree and across geographic space. Geographically, the major differences in diversification rates are hemispheric rather than latitudinal, with bird assemblages in Asia, North America and southern South America containing a disproportionate number of species from recent rapid radiations. The contribution of rapidly radiating lineages to both temporal diversification dynamics and spatial distributions of species diversity illustrates the benefits of an inclusive geographical and taxonomical perspective. Overall, whereas constituent clades may exhibit slowdowns, the adaptive zone into which modern birds have diversified since the Cretaceous may still offer opportunities for diversification.

The presented distinctness metrics are effective yet easily communicable and versatile tools to assist objective global conservation decision making. Given that most species will remain ecologically understudied, combining growing phylogenetic and spatial data may be an efficient way to retain vital aspects of biodiversity.

Accurate understanding of the global spread of emerging viruses is critically important for public health responses and for anticipating and preventing future outbreaks. Here, we elucidate when, where and how the earliest sustained SARS-CoV-2 transmission networks became established in Europe and North America. Our results suggest that rapid early interventions successfully prevented early introductions of the virus into Germany and the US from taking hold. Other, later introductions of the virus from China to both Italy and to Washington State founded the earliest sustained European and North America transmission networks. Our analyses demonstrate the effectiveness of public health measures in preventing onward transmission and show that intensive testing and contact tracing could have prevented SARS-CoV-2 from becoming established.

The immunoglobulin heavy-chain locus (IGH) encodes variable (IGHV), diversity (IGHD), joining (IGHJ), and constant (IGHC) genes and is responsible for antibody heavy-chain biosynthesis, which is vital to the adaptive immune response. Programmed V-(D)-J somatic rearrangement and the complex duplicated nature of the locus have impeded attempts to reconcile its genomic organization based on traditional B-lymphocyte derived genetic material. As a result, sequence descriptions of germline variation within IGHV are lacking, haplotype inference using traditional linkage disequilibrium methods has been difficult, and the human genome reference assembly is missing several expressed IGHV genes. By using a hydatidiform mole BAC clone resource, we present the most complete haplotype of IGHV, IGHD, and IGHJ gene regions derived from a single chromosome, representing an alternate assembly of ∼1 Mbp of high-quality finished sequence. From this we add 101 kbp of previously uncharacterized sequence, including functional IGHV genes, and characterize four large germline copy-number variants (CNVs). In addition to this germline reference, we identify and characterize eight CNV-containing haplotypes from a panel of nine diploid genomes of diverse ethnic origin, discovering previously unmapped IGHV genes and an additional 121 kbp of insertion sequence. We genotype four of these CNVs by using PCR in 425 individuals from nine human populations. We find that all four are highly polymorphic and show considerable evidence of stratification (Fst = 0.3-0.5), with the greatest differences observed between African and Asian populations. These CNVs exhibit weak linkage disequilibrium with SNPs from two commercial arrays in most of the populations tested.

In an era of accelerated biodiversity loss and limited conservation resources, systematic prioritization of species and places is essential. In terrestrial vertebrates, evolutionary distinctness has been used to identify species and locations that embody the greatest share of evolutionary history. We estimate evolutionary distinctness for a large marine vertebrate radiation on a dated taxon-complete tree for all 1,192 chondrichthyan fishes (sharks, rays and chimaeras) by augmenting a new 610-species molecular phylogeny using taxonomic constraints. Chondrichthyans are by far the most evolutionarily distinct of all major radiations of jawed vertebrates-the average species embodies 26 million years of unique evolutionary history. With this metric, we identify 21 countries with the highest richness, endemism and evolutionary distinctness of threatened species as targets for conservation prioritization. On average, threatened chondrichthyans are more evolutionarily distinct-further motivating improved conservation, fisheries management and trade regulation to avoid significant pruning of the chondrichthyan tree of life.

SignificanceStudies characterizing within-host latent HIV sequence diversity have yielded insight into reservoir dynamics and persistence. Our understanding of these processes, however, can be further enhanced if reservoir diversity is interpreted in context of HIV’s within-host evolutionary history. Approaches to infer the original establishment (i.e., integration) dates of individual within-host latent HIV lineages would be particularly useful in this regard. We describe a phylogenetic framework to infer latent HIV ages from viral sequence information and apply it to latent HIV sequences sampled up to 10 y on suppressive therapy to yield insights into HIV reservoir dynamics. The ability to infer within-host latent HIV ages from sequence information has broad potential applications that may advance us toward an HIV cure.

Summary1. Phylogenetic trees that include all member lineages are necessary for many questions in macroevolution, biogeography and conservation. Currently, producing such trees when genetic data or phenotypic characters for some tips are missing generally involves assigning missing species to the root of their most exclusive clade, essentially grafting them onto existing and static topologies as polytomies. 2. We describe an R package, 'PASTIS', that enables a two-stage Bayesian method using MrBayes version 3.2 (or higher) to incorporate lineages lacking genetic data at the tree inference stage. The inputs include a consensus topology, a set of taxonomic statements (e.g. placing species in genera and aligning some genera with each other or placing subspecies within species) and user-defined priors on edge lengths and topologies. PASTIS produces input files for execution in MrBayes that will produce a posterior distribution of complete ultrametric trees that captures uncertainty under a homogeneous birth-death prior model of diversification and placement constraints. If the age distribution of a focal node is known (e.g. from fossils), the ultrametric tree distribution can be converted to a set of dated trees. We also provide functions to visualize the placement of missing taxa in the posterior distribution. 3. The PASTIS approach is not limited to the level of species and could equally be applied to higher or lower levels of organization (e.g. accounting for all recognized subspecies or populations within a species) given an appropriate choice of priors on branching times.

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