Abstract
By Y. Kubota, K. Hukuda, F. Ishihara, M. Furukawa and Y. Shiba
Almost all the inhabitants of thirty one communities in the Upper Ina District, Nagano Prefecture, were subjected to a systematic survey. There were 4, 891 families of consanguineous marriage among 30, 984, couples, i. e. amounting to 15.79%, of which
9.88% were cousin marriages,
1.71% marriages between children of cousins and cousins,
4.19% marriages between second cousins.
Eugenic Index of Inbreeding of the population, when expressed on the cousin marriage level, was as follows:
0.0988+0.0171/2+0.0419/4=0.1178
This index, proposed by the senior author (K.H.), refers to the degree of risk apprehended on the ground of race hygiene, especiany when a simple recessive gene exists in the population. When there are no other types of consanguineous marriage than cousin marriages, their frequency corresponds to the index. When there are consanguineous marriages more remote, their frequency contribute, with due reduction, to the index of inbreeding.
Kawashima Village has the highest rate of consanguineous marriage, i. e. 28.4 (= 16.43 +3.62+8.21) %. The Eugeie Index of Inbreceding amounts to 0.2029. The community with the lowest rate of consanguineous marriage is Takatoo Town, which still has 9.5 (=6.65+1.21+1.66) S. The Index of Inbreeding, 0.0767, is still very high.
Result of further analysis will follow in separate papers.
