Preliminary reports of studies on genetic effects of consanguineous marriages. II. Incidence of subtypes of consanguineous marriages in populations of rural origin
Yanase, T.; Handa, Y.; Fujiki, N.
Proceedings of the Japan Academy 39(7): 497-502
1963
ISSN/ISBN: 0021-4280 Document Number: 239783
As far as sex-linked genes are concerned, only female progeny are under the effect of consanguineous marriages. Cousin marriages may be one of the 4 types: wife's mother is a sister of husband's mother (FF- type); wife's father is a brother of husband's mother (FM- type); wife's mother is a sister of husband's father (MF-type); wife's father is a brother of husband's father (MM-type) Similarly, uncle-neice and aunt-nephew unions may be classified into FO-, MO-, OF-, and OM-types. If mating were at random, these 4 types should occur with equal frequency. However, in most populations thus far studied, predilection for one or another type is seen. In most European and Japanese urban populations, prevalence of FF plus FM over MF plus MM may be noticed. In the Japanese rural populations studied by the authors, this tendency is less apparent due to miscellaneous causes. In such populations in Hoshino and Ohshima that were most intensively studied, tracing back to the period more than 50 years ago, temporal variation in incidence of consanguineous unions are clearly noticed. The total consanguinity rate and mean coefficient of inbreeding for autosomal genes are 22.27 and 0.001088 in Hoshino, and 22.27 and 0.00748 in Ohshima. The frequency of unions with f'>O and the mean f' (f'=inbreed-coefficient for sex-linked genes) are about 10 and 0.013 (Hoshino), and 12 and 0.010 (Ohshima). Considerations on the effect of inbreeding upon partially-sex-linked genes are also presented.