An analysis of ancient DNA suggests that forager populations living in sub-Saharan Africa around the end of the Pleistocene epoch — about 20,000 years ago — tended to live more regionally than their ancestors, providing additional insights into the population history of Africa. Studying population changes during this period remains challenging due to demographic shifts in the past 5,000 years that have obscured the structures of more ancient populations. In a study appearing in this week's in Nature, a team led by scientists from Harvard Medical School examined genome-wide ancient DNA data for six individuals from eastern and south-central Africa spanning the past approximately 18,000 years and compared it with published DNA data from 28 ancient people from the past 8,000 years. They identify three highly divergent source populations, including deeply diverged eastern and southern African lineages, plus a previously unappreciated ubiquitous distribution of ancestry that occurs in highest proportion today in central African rainforest hunter-gatherers. The findings support previous archaeological studies that pointed increasing regionalization by the end of the Pleistocene, the study's authors write. GenomeWeb has more on this, here.
A unified platform for implementing precision medicine strategies in oncology at the point-of-care is detailed in Nature Cancer this week. Called the Molecular Tumor Board Portal, the web-based system enables the sharing and use of next-generation sequencing data by researchers and clinicians, according to its developers at the Karolinska Institutet and elsewhere. It allows for the interpretation of sequencing results across the seven comprehensive cancer centers that form Cancer Core Europe, is integrated into the alliance's clinical workflows, and provides a single platform to distribute the results and support shared discussions at scale. "To our knowledge, this is an unprecedented effort for co-developing new anticancer therapies and biomarkers under a harmonized infrastructure in Europe," the scientists write.
A Karolinska Institutet-led research team describes the use of transcriptomic technologies for clonal tracing of dissociated mouse brain cells in this week's Nature Neuroscience. High-throughput single-cell RNA sequencing has revealed hundreds of molecularly distinct cell types across the entire mouse and human nervous system, yet the lineage relationships between mature cell types and progenitor cells are not well understood. To address this, the investigators used in vivo barcoding of early progenitors to simultaneously profile cell phenotypes and clonal relations in the mouse forebrain using single-cell and spatial transcriptomics. They identify fate-restricted progenitor cells in the mouse hippocampal neuroepithelium and show that microglia are derived from few primitive myeloid precursors that massively expand to generate widely dispersed progeny. Additionally, spatial transcriptomics of barcoded mouse brain tissue disentangled multiple migration patterns of progeny from brain progenitor cells. "Our findings demonstrate the utility of high-throughput clonal tracing in the mouse brain to provide molecular insights into brain development at the single-cell and tissue level," the researchers write.