Kamau L, Lehmann T, Hawley W A, Orago A S, Collins F H
Kenya Medical Research Institute, Nairobi.
Am J Trop Med Hyg. 1998 Jan;58(1):64-9. doi: 10.4269/ajtmh.1998.58.64.
Microgeographic differentiation in Anopheles gambiae from seven villages less than 10 km apart in Asembo Bay, western Kenya was estimated by analysis of variability in seven microsatellite loci. Results from the Asembo Bay villages were compared with specimens collected in Kilifi, coastal Kenya, 700 km to the east. Allele frequency distribution was very similar in all villages in Asembo Bay, but differed for the Kilifi population. Genetic differentiation among villages was low with loci-specific Fst falling within the range of 0.0000-0.0085. These low estimates of differentiation correspond to among-village migration indices greater than 5.66, suggesting a high level of gene flow within the Asembo population. The Nm value between Kilifi and Asembo Bay was 1.54, indicating much lower levels of gene flow. Average observed heterozygosity among the seven villages was in all but one case less than the expected heterozygosity, most likely indicating the presence of null alleles, but possibly the presence of randomly mating units (demes) smaller than the village. We conclude that there is likely no genetic structure at the level of the village in Asembo Bay but that gene flow is restricted between western and coastal Kenya, probably by the high elevation rift.
通过分析七个微卫星位点的变异性，对肯尼亚西部阿森博湾相距不到10公里的七个村庄的冈比亚按蚊进行了微观地理分化评估。将阿森博湾村庄的结果与在东边700公里处肯尼亚沿海的基利菲采集的样本进行了比较。阿森博湾所有村庄的等位基因频率分布非常相似，但基利菲种群的分布不同。村庄间的遗传分化较低，位点特异性Fst在0.0000 - 0.0085范围内。这些较低的分化估计值对应于大于5.66的村庄间迁移指数，表明阿森博种群内基因流动水平较高。基利菲和阿森博湾之间的Nm值为1.54，表明基因流动水平低得多。除一个村庄外，七个村庄的平均观察杂合度在所有情况下均低于预期杂合度，这很可能表明存在无效等位基因，但也可能存在比村庄小的随机交配单位（同类群）。我们得出结论，阿森博湾村庄层面可能不存在遗传结构，但肯尼亚西部和沿海之间的基因流动受到限制，可能是由于高海拔裂谷造成的。
