INAOKA Tsukasa Kumamoto Univ., School of Medicine, Instructor, 医学部, 講師 (60176386)
NAKAZAWA Minato The Univ.Tokyo, Graduate School of Med.Assist.Prof., 大学院・医学系研究科, 助手 (40251227)
HONGO Tetsuro Yamanashi Institute for Environmental Sciences, Prin.Investigator, 主幹研究員 (90199563)
ISHIDA Takafumi The Univ.Tokyo, Graduate School of Sciences, Assoc.Prof., 大学院・理学系研究科, 助教授 (20184533)
TOKUNAGA Katsushi The Univ.Tokyo, Graduate School of Med.Sci., Professor, 大学院・医学系研究科, 教授 (40163977)
The present study conclusively compared the two human populations, Gidra and Balopa, living in Papua New Guinea, based on the data collected in long-term fieldwork and analyses of biological specimens and environmental samples, from the viewpoint of adaptation of human population. Major achievements can be summarized as following three points.
1. Disease profiles at an individual level
Based on seroepidemiologic analysis for 70-80% adults of the Gidra and Balopa, comparison of disease profiles between the two populations suggested that inter-individual differences of disease experience in the Gidra can mostly be explained by genetic nature and by random exposure to environmental etiological factors, considering that their disease profile mostly consisted of communicable diseases like malaria, and the prevalence of geriatric diseases were markedly low. On the other hand, the Balopa relatively developed Westernized lifestyle and suffered from not only chronic degenerative diseases like dia
betes but also imported infectious diseases like viral hepatitis type C.
2. Relationship between the disease profiles and genetic feature or nutritional status
HLA-DRB polymorphism, which is known to have relationship with several diseases, and band-3 deletion which causes malaria resistant ovalocytosis were investigated as genetic features. Both results suggested past gene influx and malarial selection force which supported fixation of those genes. About nutritional status. difference in iron nutrition mainly due to differences in dietary pattern differentially affected the occurrence of anemia in various villages where malaria prevalence diversified.
3. Conclusive computer simulation of population dynamics
We defined the individual with genetic information, kin relations, and nutritional status, as the struct-type of C language, and conducted computer simulation of population dynamics according to the age-specific death rate fluctuating with nutritional status, genetic factor, and the exposure to malaria, and to the fertility bound to couples, where gene transmission was randomly done from each parent to an offspring. Simulation analyses suggested that the variance of genetic polymorphism tended to increase with the extent of nutritional and malarial effects on the death rate. Less