No linguists have found a language family connection between indigenous Papuan and Australian aboriginal languages and those of Asia, Africa, the Americas or any other part of the world. Indeed, no linguistic connection has been established between the indigenous languages of Melanesia and the indigenous languages of the Aboriginal Australians. This is consistent with the mainstream view, supported by population genetics and archaeology, that Papua New Guinea and Australia, as well as some of the islands neighboring Papua New Guinea, were first inhabited by hominins (humans or otherwise) at least 40,000 years ago in migrations that were either separate or swiftly segregated, and that many of these populations have had only limited contact with outside populations until the modern era. While there are plausible reasons to infer that the Melanesian languages and the aboriginal Australian languages, respectively, have common origins in a small founding population with a single language, the linguists have not been able to marshal lexical, phonetic and grammatical evidence from these languages in their current form to support these inferences. Since 2008, linguist Edward Vajda has been advocating, and attempting to demonstrate, a genetic link between the Na-Dene languages of North America and the Yeniseian languages of central Siberia, suggesting a homeland in Siberia or a back migration of Na-Dene speakers from Beringia. Na-Dene languages are spoken by Native Alaskans and some people from the First Nations of Western Canada, in the Pacific Northwest, and also includes the Southern Athabaskan languages spoken in the American Southwest (e. g., the languages Apache and Navajo). The Eskimo–Aleut languages are spoken by native peoples of the Arctic regions of Alaska and Canada and Greenland, generally to the North of Na-Dene linguistic areas (shown on the map on the left). Current ancient and modern DNA scholarship and archaeology supports a three-layer paradigm in which first the Saqqaq (Arctic Paleo-Eskimos) which was present 2000 BCE, then the Dorset (second wave Arctic Paleo-Eskimos), and finally the Thule (proto-Inuit) from ca. 500 CE – 1000 CE, successively sweep Arctic North America while having little genetic impact on Native American populations further South, that presumably have origins that date back to the initial colonization of the Americas by modern humans from Asia (who are the first hominins to live there), and ancient DNA shows genetic continuity from the Thule to modern Inuit (whose genetics are remarkably homogeneous), dominated by the A2a, A2b, and D3 mtDNA haplotypes, while "Haplotype D2 (3%), found among modern Aleut and Siberian Eskimos, was identified at a low frequency in the modern samples but not the ancient.