Jorde L B, Pitkänen K J
Department of Human Genetics, University of Utah School of Medicine, Salt Lake City 84132.
Am J Phys Anthropol. 1991 Feb;84(2):127-39. doi: 10.1002/ajpa.1330840203.
We have compiled data on the frequency of first-cousin marriages in Finland using royal dispensation records for the time period 1810-1872 and national population statistics for the time period 1878-1920. For the earlier period, 0.315% of Finland's marriages were contracted between first cousins (2,331 of 739,387). During the second time period, 0.174% of Finland's marriages took place between first cousins (1,325 of 761,976). These figures, which yield average kinship coefficients of 0.00020 and 0.00011, respectively, show that the level of inbreeding in Finland due to first-cousin marriage has been quite low. An analysis of individual parishes shows that first-cousin marriages are, on average, substantially less frequent than predicted by a random-mating model. In order to evaluate determinants of first-cousin marriage, several predictive variables have been examined: parish ethnic composition (proportion of Swedish and Finnish speakers), husband's occupation (graded into 6 socioeconomic levels), geographic distance between spouses' premarital residences, population density, parish endogamy, and urban vs. rural residence. Various logistic and linear regression models were analyzed in which consanguinity was the dependent variable. The best predictors of consanguinity were ethnic composition and occupation. The other variables were not in general significant predictors. These results show that many of the "mate availability" factors that would be predicted theoretically to account for consanguinity variation (population density, geographic isolation, urban vs. rural residence) do not. Instead, the best predictors of consanguinity at the first-cousin level are cultural factors such as ethnicity and occupation. Evaluation of cultural variables can provide a greatly enriched interpretation of complex biosocial phenomena such as inbreeding.
我们利用1810年至1872年期间的皇家特许记录以及1878年至1920年期间的全国人口统计数据，汇编了芬兰近亲结婚频率的数据。在早期，芬兰0.315%的婚姻是在表亲之间缔结的（739,387例婚姻中有2,331例）。在第二个时间段，芬兰0.174%的婚姻是在表亲之间进行的（761,976例婚姻中有1,325例）。这些数字分别得出平均亲属系数为0.00020和0.00011，表明芬兰因近亲结婚导致的近亲繁殖水平一直相当低。对各个教区的分析表明，平均而言，表亲结婚的频率大大低于随机交配模型的预测。为了评估近亲结婚的决定因素，我们研究了几个预测变量：教区的种族构成（瑞典语和芬兰语使用者的比例）、丈夫的职业（分为6个社会经济水平）、配偶婚前居住地之间的地理距离、人口密度、教区内部通婚以及城市与农村居住情况。我们分析了各种逻辑回归和线性回归模型，其中血亲关系是因变量。血亲关系的最佳预测因素是种族构成和职业。其他变量一般不是显著的预测因素。这些结果表明，理论上预计会解释血亲关系变化的许多“配偶可得性”因素（人口密度、地理隔离、城市与农村居住情况）并没有起到这样的作用。相反，在表亲层面，血亲关系的最佳预测因素是文化因素，如种族和职业。对文化变量的评估可以为近亲繁殖等复杂的生物社会现象提供更丰富的解释。
