In this week's Nature Ecology & Evolution, researchers from Temple University present a genetic study of Neanderthal DNA fragments in current-day East Asians and Europeans, revealing new insights into interbreeding between the extinct hominid species and anatomically modern humans. The scientists compiled the joint fragment frequency spectrum of European and East Asian Neanderthal fragments and compared it with both analytical theory and data simulated under various models of admixture. They then used machine learning to evaluate the models and conclude that one involving multiple episodes of interbreeding best aligns with available data. "These findings indicate a longer-term, more complex interaction between humans and Neanderthals than was previously appreciated," they write. GenomeWeb has more on this, here.
Meanwhile, in Nature Genetics, an international research team publishes a study revealing the first genome-wide significant risk loci for attention deficit/hyperactivity disorder. The investigators performed a genome-wide association meta-analysis of roughly 20,183 ADHD patients and about 35,000 controls, uncovering 12 genomic regions associated with the disorder. The researchers also identify 44 other diseases and traits that share common genetic signals with ADHD — including major depressive disorder, anorexia nervosa, and insomnia — and find candidate genes with roles in synapse formation, speech development, learning, and the regulation of dopamine. There's more on this study, here, too.
And in Nature Genetics last week, an international group led by Johns Hopkins University researchers report the deep sequencing of 910 individuals of African descent to construct a set of DNA sequences common to all the individuals but missing from the reference human genome. Their study reveals approximately 297 million base pairs in over 125,000 distinct contigs in the populations of African descent — demonstrating that the African pan-genome contains about 10 percent more DNA than the current human reference genome. "Although the functional significance of nearly all of this sequence is unknown," the authors write, "387 of the novel contigs fall within 315 distinct protein-coding genes, and the rest appear to be intergenic." GenomeWeb also covers this, here.