Research
Assessing the molecular divergence between Anopheles (Kerteszia) cruzii populations from Brazil using the timeless gene: further evidence of a species complex
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* Corresponding author: Alexandre A Peixoto apeixoto@ioc.fiocruz.br
1 Laboratório de Biologia Molecular de Insetos, Instituto Oswaldo Cruz, FIOCRUZ, Av. Brasil 4365, Rio de Janeiro 21045-900, RJ, Brazil
2 Departamento de Microbiologia e Parasitologia, CCB, Universidade Federal de Santa Catarina, Florianópolis 88040-970, SC, Brazil
3 School of Biological and Chemical Sciences, Queen Mary University of London, 327 Mile End Road, London, E1 4NS, UK
Malaria Journal 2009, 8:60 doi:10.1186/1475-2875-8-60
Published: 9 April 2009Abstract
Background
Anopheles (Kerteszia) cruzii was the most important vector of human malaria in southern Brazil between 1930–1960. Nowadays it is still considered an important Plasmodium spp. vector in southern and south-eastern Brazil, incriminated for oligosymptomatic malaria. Previous studies based on the analysis of X chromosome banding patterns and inversion frequencies in An. cruzii populations from these areas have suggested the occurrence of three sibling species. In contrast, two genetically distinct groups among An. cruzii populations from south/south-east and north-east Brazil have been revealed by isoenzyme analysis. Therefore, An. cruzii remains unclear.
Methods
In this study, a partial sequence of the timeless gene (~400 bp), a locus involved in the control of circadian rhythms, was used as a molecular marker to assess the genetic differentiation between An. cruzii populations from six geographically distinct areas of Brazil.
Results
The timeless gene revealed that An. cruzii from Itaparica Island, Bahia State (north-east Brazil), constitutes a highly differentiated group compared with the other five populations from south and south-east Brazil. In addition, significant genetic differences were also observed among some of the latter populations.
Conclusion
Analysis of the genetic differentiation in the timeless gene among An. cruzii populations from different areas of Brazil indicated that this malaria vector is a complex of at least two cryptic species. The data also suggest that further work might support the occurrence of other siblings within this complex in Brazil.