Lack of correspondence between Asian-Papuan genetic admixture and Austronesian language dispersal in eastern Indonesia.

Abstract

Xu et al. (1) argued that a west-east cline of Asian-Papuan genetic admixture across eastern Indonesia �is in excellent agreement with inferences� (ref. 1, p. 4574) regarding the expansion of Austronesian languages from Taiwan across Island Southeast Asia (ISEA) from circa 4,000 y ago. They identify two major genetic populations within ISEA, �Asian� and �Papuan,� which allegedly reflect Austronesian language expansion and New Guinea influences, respectively. However, humans initially occupied ISEA over 50,000 y ago, yet no trace of their genetic signal seemingly survives in modern-day populations. This erasure of preexisting ISEA ancestry in their study contradicts previous findings (2) and requires inclusion of comparable genetic data from mainland Southeast Asia (mSEA) to disentangle mSEA and ISEA contributions to Asian genetic ancestry.