Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, 40-007 Katowice, Poland.
Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria.
Int J Mol Sci. 2022 Mar 26;23(7):3643. doi: 10.3390/ijms23073643.
Although Crepis was the first model plant group in which chromosomal changes were considered to play an important role in speciation, their chromosome structure and evolution have been barely investigated using molecular cytogenetic methods. The aim of the study was to provide a better understanding of the patterns and directions of Crepis chromosome evolution, using comparative analyses of rDNA loci number and localisation. The chromosome base number and chromosomal organisation of 5S and 35S rDNA loci were analysed in the phylogenetic background for 39 species of Crepis, which represent the evolutionary lineages of Crepis sensu stricto and Lagoseris, including . The phylogenetic relationships among all the species were inferred from nrITS and newly obtained 5S rDNA NTS sequences. Despite high variations in rDNA loci chromosomal organisation, most species had a chromosome with both rDNA loci within the same (usually short) chromosomal arm. The comparative analyses revealed several independent rDNA loci number gains and loci repositioning that accompanied diversification and speciation in Crepis. Some of the changes in rDNA loci patterns were reconstructed for the same evolutionary lineages as descending dysploidy.
虽然瞿麦属是第一个被认为染色体变化在物种形成中起重要作用的模式植物群，但使用分子细胞遗传学方法对其染色体结构和进化的研究甚少。本研究的目的是通过对 rDNA 位点数量和定位的比较分析，更好地了解瞿麦属染色体进化的模式和方向。对代表瞿麦属和山苦荬属进化谱系的 39 种瞿麦属植物的染色体基数和 rDNA 位点的染色体组织进行了分析，包括。所有物种的系统发育关系是根据 nrITS 和新获得的 5S rDNA NTS 序列推断的。尽管 rDNA 位点的染色体组织存在高度变异，但大多数物种的两条 rDNA 位点都位于同一（通常较短）染色体臂上。比较分析显示，在瞿麦属的多样化和物种形成过程中，存在着几个独立的 rDNA 位点数量增加和位点重定位。一些 rDNA 位点模式的变化被重建为与同进化谱系的下降非整倍体同源。
