Global S&T Development Trend Analysis Platform of Resources and Environment
Modifications of histone proteins have essential roles in normal development and human disease. Recognition of modified histones by '
Pottery is one of the most commonly recovered artefacts from archaeological sites. Despite more than a century of relative dating based on typology and seriation(1), accurate dating of pottery using the radiocarbon dating method has proven extremely challenging owing to the limited survival of organic temper and unreliability of visible residues(2-4). Here we report a method to directly date archaeological pottery based on accelerator mass spectrometry analysis of C-14 in absorbed food residues using palmitic (C-16:0) and stearic (C-18:0) fatty acids purified by preparative gas chromatography(5-8). We present accurate compound-specific radiocarbon determinations of lipids extracted from pottery vessels, which were rigorously evaluated by comparison with dendrochronological dates(9,10) and inclusion in site and regional chronologies that contained previously determined radiocarbon dates on other materials(11-15). Notably, the compound-specific dates from each of the C-16:0 and C-18:0 fatty acids in pottery vessels provide an internal quality control of the results(6) and are entirely compatible with dates for other commonly dated materials. Accurate radiocarbon dating of pottery vessels can reveal: (1) the period of use of pottery
Using lipid residues absorbed in potsherds, the ages of pottery from various archaeological sites are determined and validated using sites for which the dates are well known from other methods.
A key mutational process in cancer is structural variation, in which rearrangements delete, amplify or reorder genomic segments that range in size from kilobases to whole chromosomes(1-7). Here we develop methods to group, classify and describe somatic structural variants, using data from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA), which aggregated whole-genome sequencing data from 2,658 cancers across 38 tumour types(8). Sixteen signatures of structural variation emerged. Deletions have a multimodal size distribution, assort unevenly across tumour types and patients, are enriched in late-replicating regions and correlate with inversions. Tandem duplications also have a multimodal size distribution, but are enriched in early-replicating regions-as are unbalanced translocations. Replication-based mechanisms of rearrangement generate varied chromosomal structures with low-level copy-number gains and frequent inverted rearrangements. One prominent structure consists of 2-7 templates copied from distinct regions of the genome strung together within one locus. Such cycles of templated insertions correlate with tandem duplications, and-in liver cancerfrequently activate the telomerase gene TERT. A wide variety of rearrangement processes are active in cancer, which generate complex configurations of the genome upon which selection can act.