Assessing Y-Chromosome Variation in the South Pacific Using Newly Detected NRY Markers

Abstract

The South Pacific is a region of incredible biological, cultural and linguistic diversity, reflecting its early settlement by human populations. It has been a region of interest to scholars because of this diversity, as well as its unique geography and settlement history. Current evidence suggests there was an initial settlement of Near Oceania during the Pleistocene by Papuan-speaking foragers, followed by a later Holocene settlement of Remote Oceania by Oceanic-speaking agriculturalists. Previous studies of human biological variation have been used to illuminate the migration history of and population relationships within Oceania. In this study, I analyzed Y-chromosome (NRY) diversity in 842 unrelated males to more fully characterize the phylogeography of paternal genetic lineages in this region, using a large number of regionally informative markers on an intensive sample set from Northern Island Melanesia. This approach facilitated an analysis of NRY haplogroup distributions, an evaluation of the ancestral paternal genetic contribution to the region, and a comparison of regional NRY diversity with that observed at different genetic loci (e.g., mtDNA). This project is part of a collaborative effort by faculty and graduate students from the Temple University Department of Anthropology that focused on characterizing biological variation and genetic structure in Melanesia, and better resolving the phylogeographic specificity of Northern Island Melanesia. Overall, this study generated a higher resolution view of NRY haplogroup variation than detected in previous studies through the use of newly defined and very informative SNP markers. It also showed that there is a very small ancestral East Asian paternal contribution to this area, and a rather large proportion of older Melanesian NRY lineages present there. In addition, this study observed extraordinary NRY diversity within Northern Island Melanesia, as well as genetic structure influenced more by geography than linguistic variation. This structure and diversity was essentially equivalent to that noted for mtDNA data for this region. Finally, this study helped to resolve questions about the placement of the 50f2/c deletion within the larger NRY tree. Overall, this work has refined our understanding of the migration and demographic history of Northern Island Melanesia.