Tapia-Perez Graciela, García-Vazquez Zeferino, Montaldo Hugo, George John
Facultad de Medicina Veterinaria y Zootecnia, U.N.A.M. Departamento de Genética, Av. Universidad No. 2000, Ciudad Universitaria, Col Coyoacan, C.P. 04150, Mexico.
Exp Appl Acarol. 2003;31(1-2):135-49. doi: 10.1023/b:appa.0000005143.90681.82.
The objective of this study was to evaluate the inheritance mode of resistance to flumethrin in the Mexican Aldama Boophilus microplus strain. Two Mexican strains were used, the Chiapas susceptible (SS), and the Aldama flumethrin-resistant from Tamaulipas. Six steers weighing ca. 250 kg were randomly assigned for each of six crosses: the susceptible (SS), resistant (RR), and the F1 (RS, SR) reciprocal crosses and F2 (RS x RS and SR x SR). The reciprocal crosses were made to evaluate maternal and sex linkage effects. Bioassays tested resistant and susceptible larvae along with their hybrid F1 and F2 progeny against a series of concentrations of flumethrin (0, 0.0075, 0.00150, 0.00300, 0.00600 and 0.01200 microg/g). To test the single-gene hypothesis of resistance, a nonparametric line-cross test proposed by Collins was used. The bioassay data were subjected to probit analysis and the resistance factor and effective dominance obtained. Results of this study indicated that inheritance for flumethrin resistance in the Aldama strain was autosomal and controlled for more than one gene. The F1 and F2 larvae had similar lower resistant factor (RF 2.8-4.5) while the resistant Aldama strain was 21-fold higher (RF 81.8) than the mean of the F1 and F2. The extent of flumethrin resistance in the Aldama B. microplus strain depended upon the concentration of the pesticide used. Resistance was almost dominant at the lowest dose while almost completely recessive at the highest dose. Maternal effects were shown for egg-mass. These results shown here indicate more than one gene basis of flumethrin resistance in B. microplus ticks are present. Therefore it is necessary to locate and understand the major loci for elucidate the mechanism of resistance and improve the ability to track and delay the evolution of resistance.
本研究的目的是评估墨西哥阿尔达马微小牛蜱品系对氟氯氰菊酯抗性的遗传模式。使用了两个墨西哥品系，恰帕斯敏感品系（SS）和来自塔毛利帕斯州的阿尔达马氟氯氰菊酯抗性品系。将六头体重约250千克的阉牛随机分配到六个杂交组合中：敏感（SS）、抗性（RR）以及F1（RS、SR）正反交组合和F2（RS×RS和SR×SR）。进行正反交是为了评估母体效应和性连锁效应。生物测定对抗性和敏感幼虫及其杂交F1和F2后代进行了一系列氟氯氰菊酯浓度（0、0.0075、0.00150、0.00300、0.00600和0.01200微克/克）的测试。为了检验抗性的单基因假说，采用了柯林斯提出的非参数品系杂交试验。生物测定数据进行了概率分析，并获得了抗性因子和有效显性度。本研究结果表明，阿尔达马品系对氟氯氰菊酯的抗性遗传是常染色体遗传，且受多个基因控制。F1和F2幼虫具有相似的较低抗性因子（抗性因子为2.8 - 4.5），而抗性阿尔达马品系比F1和F2的平均值高21倍（抗性因子为81.8）。阿尔达马微小牛蜱品系对氟氯氰菊酯的抗性程度取决于所用农药的浓度。在最低剂量下抗性几乎呈显性，而在最高剂量下几乎完全呈隐性。卵块表现出母体效应。此处所示结果表明微小牛蜱对氟氯氰菊酯的抗性存在多个基因基础。因此，有必要定位并了解主要基因座，以阐明抗性机制，并提高追踪和延缓抗性进化的能力。
