Multilocus analysis of introgression between two sand fly vectors of leishmaniasis
1 Laboratório de Biologia Molecular de Insetos, IOC, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
2 Dipartimento di Biologia, Università di Ferrara, Ferrara, Italy
3 Environmental Research Institute, University College Cork, Cork, Ireland
4 present address: Department of Genetics, University of Leicester, Leicester, UK
BMC Evolutionary Biology 2008, 8:141 doi:10.1186/1471-2148-8-141Published: 12 May 2008
The phlebotomine sand flies (Diptera:Psychodidae) Lutzomyia (Nyssomyia) intermedia Lutz & Neiva 1912 and Lutzomyia (Nyssomyia) whitmani Antunes & Coutinho 1932 are two very closely related species and important vectors of American cutaneous leishmaniasis. Two single-locus studies have revealed evidence for introgression between the two species in both mitochondrial and nuclear genomes. These findings have prompted the development of a multilocus approach to investigate in more detail the genetic exchanges between the two species.
We analyzed ten nuclear loci using the "isolation with migration" model implemented in the IM program, finding evidence for introgression from L. intermedia towards L. whitmani in three loci. These results confirm that introgression is occurring between the two species and suggest variation in the effects of gene flow among the different regions of the genome.
The demonstration that these two vectors are not fully reproductively isolated might have important epidemiological consequences as these species could be exchanging genes controlling aspects of their vectorial capacity.