Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.
Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 370 05 České Budějovice, Czech Republic.
Cells. 2021 Aug 28;10(9):2230. doi: 10.3390/cells10092230.
Sex chromatin is a conspicuous body that occurs in polyploid nuclei of most lepidopteran females and consists of numerous copies of the W sex chromosome. It is also a cytogenetic tool used to rapidly assess the W chromosome presence in Lepidoptera. However, certain chromosomal features could disrupt the formation of sex chromatin and lead to the false conclusion that the W chromosome is absent in the respective species. Here we tested the sex chromatin presence in 50 species of Geometridae. In eight selected species with either missing, atypical, or normal sex chromatin patterns, we performed a detailed karyotype analysis by means of comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH). The results showed a high diversity of W chromosomes and clarified the reasons for atypical sex chromatin, including the absence or poor differentiation of W, rearrangements leading to the neo-W emergence, possible association with the nucleolus, and the existence of multiple W chromosomes. In two species, we detected intraspecific variability in the sex chromatin status and sex chromosome constitution. We show that the sex chromatin is not a sufficient marker of the W chromosome presence, but it may be an excellent tool to pinpoint species with atypical sex chromosomes.
性染色质是一种明显的结构，存在于大多数鳞翅目雌性多倍体核中，由大量的 W 性染色体组成。它也是一种用于快速评估鳞翅目动物中 W 染色体存在的细胞遗传学工具。然而，某些染色体特征可能会破坏性染色质的形成，并导致错误地认为相应物种中不存在 W 染色体。在这里，我们测试了 50 种尺蛾科物种中的性染色质存在情况。在 8 种具有缺失、非典型或正常性染色质模式的选定物种中，我们通过比较基因组杂交 (CGH) 和荧光原位杂交 (FISH) 进行了详细的核型分析。结果显示了 W 染色体的高度多样性，并澄清了非典型性染色质的原因，包括 W 的缺失或分化不良、导致新 W 出现的重排、可能与核仁的关联以及多个 W 染色体的存在。在两个物种中，我们检测到性染色质状态和性染色体组成的种内变异性。我们表明，性染色质不是 W 染色体存在的充分标记，但它可能是一种很好的工具，可以指出具有非典型性染色体的物种。
