Anjos Allison, Milani Diogo, Bardella Vanessa B, Paladini Andressa, Cabral-de-Mello Diogo C
Departamento de Biologia Geral e Aplicada, Instituto de Biociências, UNESP, Rio Claro, SP, 13506-900, Brazil.
Departamento de Ecologia e Evolução, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
Chromosome Res. 2023 Jan 27;31(1):5. doi: 10.1007/s10577-023-09710-2.
Satellite DNAs (satDNAs) constitute one of the main components of eukaryote genomes and are involved in chromosomal organization and diversification. Although largely studied, little information was gathered about their evolution on holocentric species, i.e., diffuse centromeres, which, due to differences in repeat organization, could result in different evolutionary patterns. Here, we combined bioinformatics and cytogenetic approaches to evaluate the evolution of the satellitomes in Mahanarva holocentric insects. In two species, de novo identification revealed a high number of satDNAs, 110 and 113, with an extreme monomer length range of 18-4228 bp. The overall abundance of satDNAs was observed to be 6.67% in M. quadripunctata and 1.98% in M. spectabilis, with different abundances for the shared satDNAs. Chromosomal mapping of the most abundant repeats of M. quadripunctata and M. spectabilis on other Mahanarva reinforced the dynamic nature of satDNAs. Variable patterns of chromosomal distribution for the satDNAs were noticed, with the occurrence of clusters on distinct numbers of chromosomes and at different positions and the occurrence of scattered signals or nonclustered satDNAs. Altogether, our data demonstrated the high dynamism of satDNAs in Mahanarva with the involvement of this genomic fraction in chromosome diversification of the genus. The general characteristics and patterns of evolution of satDNAs are similar to those observed on monocentric chromosomes, suggesting that the differential organization of genome compartments observed on holocentric chromosomes compared with monocentric chromosomes does not have a large impact on the evolution of satDNAs. Analysis of the satellitomes of other holocentric species in a comparative manner will shed light on this issue.
卫星DNA（satDNA）是真核生物基因组的主要组成部分之一，参与染色体的组织和多样化。尽管对其进行了大量研究，但关于它们在全着丝粒物种（即弥散着丝粒）中的进化信息却很少，由于重复序列组织的差异，这可能导致不同的进化模式。在这里，我们结合生物信息学和细胞遗传学方法来评估马纳纳瓦全着丝粒昆虫卫星基因组的进化。在两个物种中，从头鉴定发现了大量的卫星DNA，分别为110个和113个，单体长度范围极广，为18 - 4228碱基对。观察到四斑马纳纳瓦中卫星DNA的总体丰度为6.67%，美丽马纳纳瓦中为1.98%，共享的卫星DNA丰度不同。四斑马纳纳瓦和美丽马纳纳瓦中最丰富重复序列在其他马纳纳瓦物种上的染色体定位强化了卫星DNA的动态性质。注意到卫星DNA的染色体分布模式各不相同，在不同数量的染色体上以及不同位置出现簇状，同时也出现分散信号或非簇状卫星DNA。总之，我们的数据证明了马纳纳瓦中卫星DNA的高度动态性，以及这一基因组部分参与该属的染色体多样化。卫星DNA的一般特征和进化模式与在单着丝粒染色体上观察到的相似，这表明与单着丝粒染色体相比，在全着丝粒染色体上观察到的基因组区域的差异组织对卫星DNA的进化没有很大影响。以比较的方式分析其他全着丝粒物种的卫星基因组将有助于阐明这一问题。
