Área de Genética, Facultad de Ciencias del Mar y Ambientales, INMAR, Universidad de Cádiz, 11510 Cádiz, Spain.
Departamento de Zoología, Genética y Antropología Física, Universidad de Santiago de Compostela, 27002 Lugo, Spain.
Int J Mol Sci. 2022 May 11;23(10):5353. doi: 10.3390/ijms23105353.
The Pleuronectiformes order, which includes several commercially-important species, has undergone extensive chromosome evolution. One of these species is , a flatfish with 2 = 42 chromosomes. In this study, a cytogenomics approach and integration with previous maps was applied to characterize the karyotype of the species. Synteny analysis of was carried out using two flatfish as a reference: and . Most chromosomes (or chromosome arms for metacentrics and submetacentrics) showed a one-to-one macrosyntenic pattern with the other two species. In addition, we studied how repetitive sequences could have played a role in the evolution of bi-armed (3, and 5-9) and acrocentric (11, 12 and 16) chromosomes, which showed the highest rearrangements compared with the reference species. A higher abundance of TEs (Transposable Elements) and other repeated elements was observed adjacent to telomeric regions on chromosomes 3, 7, 9 and 16. However, on chromosome 11, a greater abundance of DNA transposons was detected in interstitial BACs. This chromosome is syntenic with several chromosomes of the other two flatfish species, suggesting rearrangements during its evolution. A similar situation was also found on chromosome 16 (for microsatellites and low complexity sequences), but not for TEs (retroelements and DNA transposons). These differences in the distribution and abundance of repetitive elements in chromosomes that have undergone remodeling processes during the course of evolution also suggest a possible role for simple repeat sequences in rearranged regions.
鲽形目鱼类，包括一些具有商业重要性的物种，经历了广泛的染色体进化。其中一种是 ，一种具有 2n = 42 条染色体的比目鱼。在这项研究中，应用细胞基因组学方法并结合以前的图谱，对该物种的核型进行了特征描述。使用两种比目鱼作为参考，对 进行了共线性分析： 和 。大多数 染色体（或中着丝粒和亚中着丝粒的染色体臂）与其他两个物种显示出一对一的宏共线性模式。此外，我们研究了重复序列如何在 双着丝粒（3、和 5-9）和近端着丝粒（11、12 和 16）染色体的进化中发挥作用，与参考物种相比，这些染色体发生了最高的重排。在染色体 3、7、9 和 16 的端粒区域附近观察到更高丰度的 TEs（转座元件）和其他重复元件。然而，在染色体 11 上，在染色体间 BAC 中检测到更多的 DNA 转座子。该染色体与其他两种比目鱼的几条染色体具有共线性，表明在其进化过程中发生了重排。在染色体 16 上也发现了类似的情况（微卫星和低复杂度序列），但不是 TEs（反转录元件和 DNA 转座子）。在经历重塑过程的染色体中，重复元件的分布和丰度的这些差异也表明简单重复序列在重排区域可能具有一定作用。
