de Arcanjo Amanda Paulino, Cabral-de-Mello Diogo Cavalcanti, Barros e Silva Ana Emília, de Moura Rita de Cássia
Departamento de Biologia, Instituto de Ciencias Biológicas, UPE-Universidade de Pernambuco, 50100-130, Recife, Brazil.
J Genet. 2009 Aug;88(2):177-82. doi: 10.1007/s12041-009-0025-y.
Mitotic and meiotic chromosomes of several populations of Eurysternus caribaeus (Coleoptera: Scarabaeidae) were analysed through conventional staining, C-banding, base-specific fluorochromes, silver nitrate staining and fluorescent in situ hybridization (FISH). All specimens showed 2n = 8 in their karyotypes, with a neo-XY sex system (Y is a submetacentric and X a metacentric) and three pairs of submetacentric autosomes. The analysis of constitutive heterochromatin (CH) revealed small blocks located in the centromeric region of all chromosomes which do not present positive staining under the fluorochromes CMA3 and DAPI. Silver nitrate staining revealed that the nucleolar organizer region (NORs) is associated with the sex chromosomes. The FISH technique revealed that rDNA sites in the X and Y are different in size. Data from different populations indicate that the diploid number reduction (2n = 8) observed in E. caribaeus is established and presumably has preceded the dispersion of this species. Moreover, this reduction occasioned the translocation of rDNA sites to the sex chromosomes, X and Y, an uncommon pattern in Scarabaeidae that was observed for the first time by the FISH in this work.
通过常规染色、C带、碱基特异性荧光染料、硝酸银染色和荧光原位杂交（FISH）对加勒比宽背鳃金龟（鞘翅目：鳃金龟科）几个种群的有丝分裂和减数分裂染色体进行了分析。所有标本的核型均显示2n = 8，具有新XY性别系统（Y为亚中着丝粒染色体，X为中着丝粒染色体）和三对亚中着丝粒常染色体。组成型异染色质（CH）分析显示，所有染色体的着丝粒区域都有小的块状物，在荧光染料CMA3和DAPI下不呈现阳性染色。硝酸银染色显示核仁组织区（NORs）与性染色体相关。FISH技术显示X和Y染色体上的核糖体DNA（rDNA）位点大小不同。来自不同种群的数据表明，在加勒比宽背鳃金龟中观察到的二倍体数目减少（2n = 8）是确定的，并且可能在该物种扩散之前就已发生。此外，这种减少导致rDNA位点易位到性染色体X和Y上，这是鳃金龟科中一种罕见的模式，在本研究中通过FISH首次观察到。
