Mazzoni Camila J, Souza Nataly A, Andrade-Coelho Claudia, Kyriacou Charalambos P, Peixoto Alexandre A
Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz--Fiocruz, Rio de Janeiro, Brazil.
BMC Evol Biol. 2006 Oct 27;6:85. doi: 10.1186/1471-2148-6-85.
Lutzomyia intermedia and Lutzomyia whitmani (Diptera: Psychodidae) are important and very closely related vector species of cutaneous leishmaniasis in Brazil, which are distinguishable by a few morphological differences. There is evidence of mitochondrial introgression between the two species but it is not clear whether gene flow also occurs in nuclear genes.
We analyzed the molecular variation within the clock gene period (per) of these two species in five different localities in Eastern Brazil. AMOVA and Fst estimates showed no evidence for geographical differentiation within species. On the other hand, the values were highly significant for both analyses between species. The two species show no fixed differences and a higher number of shared polymorphisms compared to exclusive mutations. In addition, some haplotypes that are "typical" of one species were found in some individuals of the other species suggesting either the persistence of old polymorphisms or the occurrence of introgression. Two tests of gene flow, one based on linkage disequilibrium and a MCMC analysis based on coalescence, suggest that the two species might be exchanging alleles at the per locus.
Introgression might be occurring between L. intermedia and L. whitmani in period, a gene controlling behavioral rhythms in Drosophila. This result raises the question of whether similar phenomena are occurring at other loci controlling important aspects of behavior and vectorial capacity.
中间罗蛉和惠特曼罗蛉（双翅目：蛾蠓科）是巴西皮肤利什曼病重要且密切相关的病媒物种，二者可通过一些形态差异区分开来。有证据表明这两个物种之间存在线粒体渐渗，但尚不清楚核基因中是否也发生基因流。
我们分析了巴西东部五个不同地点的这两个物种的生物钟基因周期（per）内的分子变异。AMOVA和Fst估计结果表明，物种内不存在地理分化证据。另一方面，两个物种之间的这两项分析值均具有高度显著性。与排他性突变相比，这两个物种没有固定差异，且共享多态性数量更多。此外，在另一个物种的一些个体中发现了一些一个物种“典型”的单倍型，这表明要么是古老多态性的持续存在，要么是渐渗的发生。两项基因流测试，一项基于连锁不平衡，另一项基于溯祖的MCMC分析，表明这两个物种可能在per位点交换等位基因。
中间罗蛉和惠特曼罗蛉在控制果蝇行为节律的周期基因上可能正在发生渐渗。这一结果引发了一个问题，即类似现象是否也在控制行为和媒介能力重要方面的其他位点发生。
