The formation of human populations in South and Central Asia

By sequencing 523 ancient humans, we show that the primary source of ancestry in modern South Asians is a prehistoric genetic gradient between people related to early hunter-gatherers of Iran and Southeast Asia. After the Indus Valley Civilization’s decline, its people mixed with individuals in the southeast to form one of the two main ancestral populations of South Asia, whose direct descendants live in southern India. Simultaneously, they mixed with descendants of Steppe pastoralists who, starting around 4000 years ago, spread via Central Asia to form the other main ancestral population. The Steppe ancestry in South Asia has the same profile as that in Bronze Age Eastern Europe, tracking a movement of people that affected both regions and that likely spread the distinctive features shared between Indo-Iranian and Balto-Slavic languages

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Upward fluxes of particulate organic matter in the deep North Pacific

The flux of particulate matter through the oceanic water column is a primary component in elemental cycling and is generally perceived as being in one direction: downward1,2. The organic matter constituting these particles is produced through photosynthesis in surface waters and either sinks directly as phytoplankton and products3,4 or undergoes various trophic transformations through the water column. A large proportion of the particulate organic matter produced in surface waters is regenerated in the euphotic zone5-7. A fraction of this organic matter, however, leaves the surface waters and settles through the water column, generally decreasing in quantity and changing in quality with increasing distance from the surface8-11. Although the net transport of organic matter must be downward to fuel the lower portions of the water column, there is also an upward component to transport. Positively buoyant particles, including lipid-rich eggs, larvae and, possibly, carcasses of deep-sea animals are examples of particles which undergo upward transport12,13. A previous attempt to quantify the upward mass flux indicated rates of 1-4% of the downward mass flux14. Here we report the first evidence that there is a significant upward flux of particulate organic matter, up to 66.7% of the concurrently measured downward flux, at two stations in the deep North Pacific. Given this magnitude, the previously ignored upward flux of such organic matter must be considered in models of carbon and nitrogen cycling in the open ocean. © 1989 Nature Publishing Group

Pension reforms, risk transfer and housing finance innovations

Weak housing creditor protection, accentuated by weak landed property rights and underdeveloped credit information systems constitute major constraints to housing finance development in many developing countries. Improving housing creditor protection require further institutional development and financial innovation. As a trigger of financial innovation, regulation has spawned pension reforms leading to the global shift from defined benefit to defined contribution pension schemes, which has created new opportunities to improve housing creditor protection and thus engender housing finance innovations. This paper considers how pension assets—accumulated benefits and associated personal, employment and contribution information—has provided a basis for collateralized lending and an additional avenue for credit information system development. The paper proposes a pension asset-backed creditor protection model that utilizes defined contribution pension assets to improve housing credit allocation, and thus, housing finance development. Pension assets represent alternative or complementary collateral assets for securing a housing credit (mortgage). And as depositories of information, the information content of pension assets and institutions could also be used alternatively and complementarily to assess the capacity, character and contribution (equity) of potential borrowers in the credit underwriting process. Future applied research may consider how the proposed model could be integrated in existing credit underwriting systems and the operational challenges that could emerge