A standard cytogenetic map forAnopheles sundaicus(Diptera: Culicidae) and evidence for chromosomal differentiation in populations from Thailand and Indonesia

Abstract

A standard photographic map of polytene chromosomes of Anopheles sundaicus was constructed from ovarian nurse cells and is described herein. Polytene chromosomes of wild specimens collected from 9 different geographical areas in Thailand and Indonesia have been analyzed. Specimens from these populations appear to share banding patterns with standard gene arrangements, except for some specimens from Purworejo, in Central Java, and South Tapanuli and Asahan, both of North Sumatra, which exhibited distinct banding patterns at the tip of chromosome X (Xb) compared with the standard sequence (Xa). Moreover, some specimens collected from Asahan, North Sumatra, consistently showed distinct loosely diffuse bands in zone 19 of chromosome arm 2R (2Rb) compared with the standard banding patterns (2Ra). The existence of the 2Rb pattern correlates perfectly with the presence of an extra block of centromeric heterochromatin in autosome 2 as revealed by mitotic karyotype analysis (2n = 6). These cytological differences have led to the recognition of 3 distinct forms, viz., A, B, and C, within the taxon An. sundaicus. In addition, forms A and C show a normal size for chromosome Y, (Y1), while form B has a relatively larger type of chromosome Y, (Y2). Form A is widely distributed in Thailand and Indonesia, while form B has been found in North Sumatra and Central Java. Form C, however, has been found only in Asahan, North Sumatra. Key words : Anopheles sundaicus, polytene chromosome map, mitotic karyotype, chromosomal differentiation.

Molecular Evidence of Speciation Between Island and Continental Populations ofAnopheles(Cellia)sundaicus(Diptera: Culicidae), a Principal Malaria Vector Taxon in Southeast Asia

“…sundaicus was Þrst suggested from ecological and behavioral variations (Chow 1970, Brandling-Bennett et al 1981, Kumari et al 1993, Nguyen Tang Am et al 1993, Kumari and Sharma 1994, Das et al 1997, Chang Moh Seng et al 2001). Subsequently, Sukowati and Baimai (1996) and Sukowati et al (1999) deÞned cytogenetic and isoenzymatic forms among An. sundaicus populations in Thailand and Indonesia.…”

“…that are characterized by different polytene chromosome banding patterns (Sukowati and Baimai 1996) and enzyme proÞles (Sukowati et al 1999) is essential to better understand the Sundaicus Complex. Because Sukowati and Baimai (1996) found only chromosomal form A in Trat Province of Thailand, it is most likely the continental species recognized in this article as An. sundaicus species A.…”

“…Form A was shown to occur in Sumatra and Thailand, form B was found only in northern Sumatra and central Java, and form C was restricted to Asahan in northern Sumatra. Asahan was the only site where all three cytotypes were found in sympatry (Sukowati and Baimai 1996). Isozyme analysis (Sukowati et al 1999) provided further evidence that these three forms are separate genetic entities.…”

“…land, Java, and Sumatra resulted in the discovery of three chromosomal forms (A, B, and C) (Sukowati and Baimai 1996). Form A was shown to occur in Sumatra and Thailand, form B was found only in northern Sumatra and central Java, and form C was restricted to Asahan in northern Sumatra.…”

Anopheles species diversity and distribution of the malaria vectors of Thailand

“…The valid species or genetic forms include species A, B, C, D, and E (Dusfour et al [76] and http:// mosquito-taxonomic-inventory.info/sites/mosquitotaxonomic-inventory.info/files/Subgenus%20Cellia% 20classification_14.pdf). The possible existence of a sibling species complex was first reported by Sukowati and Baimai [77] based on chromosomal variations among three identified cytological forms (A, B, and C) distributed between Thailand and Indonesia. In Thailand (Trat and Phangnga Provinces), only the A form was initially detected.…”