Deep histories in New Guinea: Insights from human genetics on regional demography and archaic introgression

In this, the first of three linked chapters oriented to human biology—specifically, genetics and genomics—we selectively review and synthesise aspects of research in the discipline that shed light on the deep histories of New Guinea’s indigenous inhabitants. Since these histories predate modern boundaries, we draw on and integrate data from across the island, east as well as west, and relate them to the broader region. Anthropological genetic research over the past century has been crucially conditioned not only by conceptual advances but also—on an extraordinary scale recently—by technological ones. As a result, the literature available for our review is very much more informative than 30 years ago. Newton-like, it can provide insights not dreamed of then. We review two themes in particular here: first, the dispersals of Homo sapiens to Sahul and their ancient interactions with other hominin species, if not in New Guinea then en route there; and second, the deep connections of New Guinean populations with other populations in the region. On the second theme, we also present new analyses of ancient effective population size changes within, and splits between, regional populations, incorporating data on the Korowai of West New Guinea. Having noted some of the remarkable findings of recent years, we close by contemplating the prospect of many deep histories yet to be told in, and about, this extraordinarily diverse yet still under-researched island.