Centro de Estudios e Investigaciones, Universidad Nacional de Quilmes, Bernal, Buenos Aires Argentina.
Genet Mol Biol. 2009 Oct;32(4):740-7. doi: 10.1590/S1415-47572009005000073. Epub 2009 Dec 1.
Pseudacteon flies, parasitoids of worker ants, are being intensively studied as potentially effective agents in the biological control of the invasive pest fire ant genus Solenopsis (Hymenoptera: Formicidae). This is the first attempt to describe the karyotype of P. curvatus Borgmeier, P. nocens Borgmeier and P. tricuspis Borgmeier. The three species possess 2n = 6; chromosomes I and II were metacentric in the three species, but chromosome pair III was subtelocentric in P. curvatus and P. tricuspis, and telocentric in P. nocens. All three species possess a C positive band in chromosome II, lack C positive heterochromatin on chromosome I, and are mostly differentiated with respect to chromosome III. P. curvatus and P. tricuspis possess a C positive band, but at different locations, whereas this band is absent in P. nocens. Heterochromatic bands are neither AT nor GC rich as revealed by fluorescent banding. In situ hybridization with an 18S rDNA probe revealed a signal on chromosome II in a similar location to the C positive band in the three species. The apparent lack of morphologically distinct sex chromosomes is consistent with proposals of environmental sex determination in the genus. Small differences detected in chromosome length and morphology suggests that chromosomes have been highly conserved during the evolutionary radiation of Pseudacteon. Possible mechanisms of karyotype evolution in the three species are suggested.
拟寄生在工蚁身上的伪叶甲蝇正被作为入侵性害虫红火蚁属（膜翅目：蚁科）生物防治的潜在有效因子而被深入研究。这是首次尝试描述 P. curvatus Borgmeier、P. nocens Borgmeier 和 P. tricuspis Borgmeier 的染色体组型。这三个物种的 2n = 6；染色体 I 和 II 在这三个物种中都是着丝粒染色体，但染色体对 III 在 P. curvatus 和 P. tricuspis 中是亚端着丝粒，在 P. nocens 中是端着丝粒。这三个物种的染色体 II 都有一个 C 带阳性，染色体 I 上没有 C 带异染色质，而主要在染色体 III 上有所区别。P. curvatus 和 P. tricuspis 都有一个 C 带阳性，但位置不同，而 P. nocens 则没有这个带。荧光带型显示，异染色质带既不是 AT 也不是 GC 丰富。用 18S rDNA 探针进行原位杂交，在三个物种的相似位置上，在染色体 II 上显示出一个信号。明显缺乏形态上明显不同的性染色体与该属环境性别决定的提议一致。染色体长度和形态的微小差异表明，在伪叶甲属的进化辐射过程中，染色体高度保守。这三个物种的染色体组型进化的可能机制被提出。
