Saugstad L F, Odegård O
Ann Hum Genet. 1977 May;40(4):419-30.
The marriages contracted between 1600 and 1850 in the parishes Vang and Slidre in the mountain valley of Valdres in Norway were investigated, using the information in the genealogical and local history of the parishes and in various public archives. The parishes functioned as a marriage isolate, in spite of regular communication with neighbouring districts. Only 54 of 4334 marriages were with residents outside the parishes, and marriages with a non-farming class (clergy) were as rare (47); 1130 marriages were probably between offspring of crofters and independent farmers. The further analysis concerns 3103 marriages contracted by the eldest sons and other heirs to 463 of the 493 farms, with members of the farming class within the parishes. Because of the linear settlement with clusters of same-named farms along both sides of the river, marital distance was measured by counting the number of farm-clusters (neighbourhood steps) between places of birth. In comparison with expectation when the marriage partner is chosen at random, marriages within the cluster occurred 13 times more frequently than expected, with an adjoining cluster 8 times more frequently and with a neighbour 1-2 clusters away 6 times as frequently as expected. One-third of the 3103 marriages were contracted within a distance of two clusters or less, and 60% eight clusters or less apart. A marital distance of 15 clusters (= 7 km) included 74% of the marriages. The predominance of a marriage pattern based on such geographical proximity must necessarily imply similarity in genetic structure of the descendants. Close consanguineous mating was apparently consciously avoided. This extreme geographical proximity of the spouses of heirs to the independent farms is probably explained by the function of a marriage as a contract to benefit the farm: promoting good neighbourliness and preventing quarrels and lawsuits related to the already very complicated ownership of cultivated land.
利用挪威瓦尔德雷斯山谷教区的族谱、地方历史以及各类公共档案中的信息，对1600年至1850年间在该教区旺格和斯利德雷所缔结的婚姻进行了调查研究。尽管与相邻地区有定期交流，但这些教区在婚姻方面呈现出相对隔离的状态。在4334桩婚姻中，仅有54桩是与教区外居民缔结的，与非农业阶层（神职人员）的婚姻同样稀少（47桩）；1130桩婚姻可能是佃农和独立农民的后代之间的结合。进一步的分析涉及493个农场中463个农场的长子及其他继承人与教区内农业阶层成员缔结的3103桩婚姻。由于沿着河流两岸存在同名农场聚集的线性聚居模式，婚姻距离通过计算出生地之间的农场聚居群数量（邻里步数）来衡量。与随机选择婚姻伴侣的预期情况相比，聚居群内的婚姻发生频率比预期高出13倍，与相邻聚居群的婚姻发生频率比预期高出8倍，与相隔1 - 2个聚居群的邻居的婚姻发生频率比预期高出6倍。在3103桩婚姻中，三分之一是在两个或更少聚居群的距离内缔结的，60%是在八个或更少聚居群的距离内。15个聚居群（= 7公里）的婚姻距离涵盖了74%的婚姻。基于这种地理 proximity 的婚姻模式占主导地位必然意味着后代的基因结构相似。显然，近亲结婚是有意识地被避免的。独立农场继承人的配偶之间这种极端的地理 proximity 可能是因为婚姻作为一种有利于农场的契约发挥了作用：促进睦邻友好，防止与已经非常复杂的耕地所有权相关的争吵和诉讼。
