In this week's Nature Communications, a team led by University of Potsdam researchers reports the nearly complete mitochondrial genome of the South American native ungulate Macrauchenia patachonica, a member of an extinct class of animals whose unusual mix of morphological traits has puzzled scientists. Using new sequencing and mapping techniques, the team assembled the mitochondrial genome from ancient DNA collected from Macrauchenia fossil samples, then used the sequences in phylogenetic analyses to assess the evolutionary relationships of these animals. The work highlights the potential for reconstructing ancient genomes even without the availability of reference genomes from living relatives.
And in Nature Biotechnology, investigators from Illumina and the University of Washington describe a new approach for haplotype-resolved genome sequencing that overcomes key limitations of existing methods. Their technique involves barcode partitioning of long DNA molecules in a single compartment using so-called on-bead barcoded tagmentation. "The key to the method … is transposon-mediated transfer of homogenous populations of barcodes from beads to individual long DNA molecules that get fragmented at the same time," the authors say. "These are then processed to sequencing libraries wherein all sequencing reads originating from each long DNA molecule share a common barcode." The result is a plate-scalable and automatable method for haplotype-resolved sequencing and phasing of structural variants of the genome.