Laboratório de Citogenética de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa, P.H. Rolfs Avenue, Viçosa 36570-900, Minas Gerais, Brazil.
Departamento de Biologia Geral e Aplicada, Instituto de Biociêcias/IB, UNESP-Universidade Estadual Paulista, 24 A Avenue, Rio Claro 13506-900, São Paulo, Brazil.
Genes (Basel). 2023 Feb 6;14(2):418. doi: 10.3390/genes14020418.
Among Meliponini species, -heterochromatin can occupy large portions of chromosomes. This characteristic could be useful for understanding evolutionary patterns of satellite DNAs (satDNAs), although few sequences have been characterized in these bees. In , phylogenetically represented by clades A and B, the -heterochromatin is mostly located in one chromosome arm. Here we used different techniques, including restriction endonucleases and genome sequencing followed by chromosomal analysis, to identify satDNAs that may be contributing to the evolution of -heterochromatin in . Our results revealed a highly abundant ThyaSat01-301 satDNA, corresponding to about 13.77% of the genome. Another seven satDNAs were identified, one corresponding to 2.24%, and the other six corresponding to 0.545% of the genome. The satDNA ThyaSat01-301 was shown to be one of the main constituents of the -heterochromatin of this species, as well as of other species belonging to clade B of . However, this satDNA was not observed on the chromosomes of species from clade A, demonstrating that the -heterochromatin is evolving divergently between species of clade A and B, as a consequence of the evolution of repetitive DNA sequences. Finally, our data suggest the molecular diversification of the karyotypes, despite a conservated macrochromosomal structure on the genus.
在蜜蜂科中，-异染色质可以占据染色体的大部分。这一特征对于理解卫星 DNA（satDNA）的进化模式可能很有用，尽管这些蜜蜂中的少数序列已经被表征。在 中，由 A 和 B 两个进化枝代表，-异染色质主要位于一条染色体臂上。在这里，我们使用了不同的技术，包括限制性内切酶和基因组测序后进行染色体分析，以鉴定可能导致 中 -异染色质进化的 satDNA。我们的结果揭示了一种高度丰富的 ThyaSat01-301 satDNA，约占 基因组的 13.77%。还鉴定了另外七个 satDNA，一个对应于 2.24%，另外六个对应于基因组的 0.545%。证明 ThyaSat01-301 satDNA 是该物种 -异染色质的主要成分之一，也是属于 B 进化枝的其他物种的主要成分之一。然而，在属于 A 进化枝的物种的染色体上没有观察到这种 satDNA，这表明 A 和 B 进化枝的物种之间的 -异染色质是通过重复 DNA 序列的进化而发生分歧进化的。最后，尽管在属中存在保守的大染色体结构，但我们的数据表明核型的分子多样化。
