We studied the karyotype and chromosomal distribution of 18S rDNA clustered in nucleolar organizer regions (NORs) in Nysius graminicola (Kolenati, 1845), belonging to the subfamily Orsillinae (Lygaeidae). It is shown that this species has a karyotype with 2n = 22(18+mm+XY), previously known in only one of 24 studied species of the genus Nysius Dallas, 1852, characterized by a similar karyotype, 2n = 14(12+mm+XY). In N. graminicola, 18S loci are located on sex chromosomes, which is a previously unknown trait for this genus. Our results in a compilation with previous data revealed dynamic evolution of rDNA distribution in Nysius. It is concluded that molecular chromosomal markers detected by FISH contribute to a better understanding of the structure and evolution of the taxonomically complex genus Nysius.

中文翻译：

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Nysius Dallas, 1852（半翅目、异翅目、Lygaeidae）的核型多样性比您想象的要大得多

 我们研究了 Nysius graminicola (Kolenati, 1845)（属于 Orsillinae (Lygaeidae) 亚科）核仁组织区 (NOR) 中聚集的 18S rDNA 的核型和染色体分布。结果表明，该物种具有 2n = 22(18+mm+XY) 的核型，之前仅在 Nysius Dallas 属 24 个研究物种之一中已知，1852 年，其特征是相似的核型，2n = 14(12+毫米+XY）。在 N. graminicola 中，18S 基因座位于性染色体上，这是该属以前未知的特征。我们对之前数据的汇编结果揭示了 Nysius 中 rDNA 分布的动态演化。结论是，FISH 检测到的分子染色体标记有助于更好地了解分类学上复杂的 Nysius 属的结构和进化。