1. ¹Department of International Affairs and Tropical Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
2. ²School of Medicine and Health Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
3. ³Department of Anthropology, Binghamton University, Binghamton, NY, USA
4. ⁴Wewak General Hospital, Wewak, Papua New Guinea
5. ⁵Department of Medicine, Karolinska Institute, Stockholm, Sweden

Correspondence: Francis Wanak Hombhanje, Department of International Affairs and Tropical Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan. Fax: +81-3-52697422. E-mail: takahiro@research.twmu.ac.jp

Received 18 August 2005; Accepted 16 November 2005; Published online 21 January 2006.

Abstract

The 27-bp deletion in the erythrocyte band 3 gene (B327) constitutes a genetic basis for Southeast Asian and Melanesian ovalocytosis. The distribution of B327 has been interpreted to reflect malaria selection or dispersal of the recent expansion of Austronesian-speaking populations. To explore these two hypotheses, we examined eight malarious populations of the East Sepik Province of Papua New Guinea (PNG) that speak both the Austronesian and Papuan languages. The B327 allele frequencies within populations were not positively correlated with malaria endemicities. In contrast, statistically significant geographical variations in the B327 allele distribution were observed. B327 was high (0.06-0.07) in the islands, intermediate (0.02-0.03) in coastal regions, but was absent or rare (0.00-0.01) in inland populations. Furthermore, the prevalence of the mitochondrial DNA region V 9-bp deletion, associated with the Austronesian expansion, was significantly correlated with that of B327. These results suggest that B327 was introduced by Austronesian-speaking people within the past 3,500 years and susequently expanded to populations along the coasts and islands of PNG. This study highlights the contribution of population origins, patterns of gene flow, disease selection and genetic drift in determining the genetic compositions of present populations.