Hijazi S S, Abulaban A, Ammarin Z, Flatz G
Trop Geogr Med. 1983 Jun;35(2):157-61.
Lactose tolerance tests with breath hydrogen determination identified 39 lactose malabsorbers among 162 Jordanian Bedouins (24%), and 111 lactose malabsorbers among 148 subjects from the urban/agricultural zone of western Jordan and Palestine (75%). This highly significant difference supports the hypothesis that milk dependence in nomadic desert populations resulted in selective pressures in favour of the lactase persistence gene. Within the urban/agricultural zone which extends from the desert border in Jordan to the Mediterranean shore, a significant increase in the frequency of lactose malabsorbers (and hypolactasia gene frequencies) from east to west was observed. The suggested genetic cline is problably due to migration from the desert populations to the agricultural zone.
通过测定呼出气中氢气进行乳糖耐量试验发现，162名约旦贝都因人中有39人乳糖吸收不良（24%），而约旦西部和巴勒斯坦城市/农业区的148名受试者中有111人乳糖吸收不良（75%）。这一高度显著的差异支持了这样一种假说，即游牧沙漠人群对牛奶的依赖导致了有利于乳糖酶持续存在基因的选择压力。在从约旦沙漠边界延伸至地中海沿岸的城市/农业区内，观察到乳糖吸收不良者的频率（以及低乳糖酶血症基因频率）从东向西显著增加。所提示的基因渐变可能是由于沙漠人群向农业区的迁移所致。
