Surendran S N, Abhayawardana T A, De Silva B G, Ramasamy R, Ramasamy M S
Department of Zoology, Faculty of Science, University of Jaffna, Sri Lanka.
Med Vet Entomol. 2000 Dec;14(4):437-40. doi: 10.1046/j.1365-2915.2000.00264.x.
In Sri Lanka, malaria is transmitted mainly by Anopheles culicifacies Giles sensu lato (Diptera: Culicidae). In India, this nominal taxon comprises sibling species A, B, C, D and E, distinguished by their chromosome morphology. Species B (identified by polytene chromosome sequence Xab, 2g1 + h1) is not such an efficient vector of malaria as other members of the An. culicifacies complex in India. All specimens of An. culicifacies s.l. examined from Sri Lanka possess Xab, 2g1 + h1 polytenes, previously interpreted as species B, despite their important vector status. Recently, species E was described from Rameshwaram Island (Tamil Nadu, India) between Sri Lanka and the Indian mainland, where both species B and E are sympatric. Species B and E share polytene sequence Xab, 2g1 + h1 but differ by the mitotic Y-chromosome being acrocentric in species B, submetacentric in species E, the latter implicated as vector of vivax malaria. From May 1999 to January 2000, we surveyed Y-chromosomes of male progeny from An. culicifacies Xab, 2g1 + h1 females collected from cattle bait in diverse malarious districts of Sri Lanka: Badulla, Monaragala, Puttalam and Trincomalee. Karyotypes of readable quality were obtained from 42/83 families examined, with overall proportions 24% acrocentric and 76% submetacentric Y-chromosome carriers, both types being sympatric in at least 3/4 localities sampled. By analogy with the situation on Rameshwaram Island, we interpret these observations to demonstrate widespread presence of two members of the An. culicifacies complex in Sri Lanka, their karyotypes being compatible with species B and E, the latter predominant and having greater vector potential.
在斯里兰卡，疟疾主要由嗜人按蚊广义种（双翅目：蚊科）传播。在印度，这个分类单元包含A、B、C、D和E五个同胞种，可通过它们的染色体形态加以区分。B种（由多线染色体序列Xab、2g1 + h1鉴定）作为疟疾传播媒介的效率不如印度嗜人按蚊复合体的其他成员。从斯里兰卡采集的所有嗜人按蚊广义种标本都具有Xab、2g1 + h1多线染色体，以前被解释为B种，尽管它们具有重要的媒介地位。最近，在位于斯里兰卡和印度大陆之间的拉梅斯沃勒姆岛（印度泰米尔纳德邦）发现了E种，B种和E种在那里同域分布。B种和E种共享多线序列Xab、2g1 + h1，但在有丝分裂Y染色体方面存在差异，B种的Y染色体为近端着丝粒，E种的Y染色体为亚中着丝粒，后者被认为是间日疟原虫的传播媒介。1999年5月至2000年1月，我们对从斯里兰卡不同疟疾流行区（巴杜勒、莫纳勒加拉、普塔勒姆和亭可马里）的牛诱饵上采集的嗜人按蚊Xab、2g1 + h1雌性个体的雄性后代的Y染色体进行了调查。在所检查的83个家族中，有42个获得了可读质量的核型，总体比例为近端着丝粒Y染色体携带者占24%，亚中着丝粒Y染色体携带者占76%，这两种类型在至少3/4的采样地点同域分布。根据拉梅斯沃勒姆岛的情况类推，我们将这些观察结果解释为表明斯里兰卡广泛存在嗜人按蚊复合体的两个成员，它们的核型与B种和E种相符，后者占主导地位且具有更大的传播媒介潜力。
