Asymmetrical canina meiosis is accompanied by the expansion of a pericentromeric satellite in non-recombining univalent chromosomes in the genus Rosa
Asymmetrical canina meiosis is accompanied by the expansion of a pericentromeric satellite in non-recombining univalent chromosomes in the genus Rosa
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DOI：
10.1093/aob/mcaa028
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发表时间：
2020-02
期刊：
影响因子：
4.2
通讯作者：
J. Lunerová;V. Herklotz;Melanie Laudien;Radka Vozárová;Marco Groth;A. Kovařík;C. Ritz
中科院分区：
文献类型：
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作者：
J. Lunerová;V. Herklotz;Melanie Laudien;Radka Vozárová;Marco Groth;A. Kovařík;C. Ritz
摘要背景与目的犬蔷薇科（Rosa sect. Caninae）尽管具有丰富的奇倍性（2n = 5x = 35），但由于其独特的减数分裂，它们能够有性繁殖。在犬减数分裂过程中，两组染色体形成二价体，由雄性和雌性配子传递，而其余染色体形成一价体，仅由卵细胞传递。因此，预计染色体的进化是由它们在减数分裂期间的行为驱动的。方法利用卫星和核糖体DNA探针对4只犬（2个亚组）有丝分裂和减数分裂染色体进行荧光原位杂交，以了解染色体的差异进化。利用高通量测序数据，分析了20个蔷薇属植物的五倍体、四倍体和二倍体，确定了卫星重复序列的丰度和多样性。关键结果在所有蔷薇属植物中均发现了CANR4的近中心卫星重复序列，包括基部亚属Hulthemia和Hesperhodos。该卫星分布在多条染色体上（每个有丝分裂细胞5-20个位点），其基因组丰度在五倍体犬鼠中（2.3%）高于非犬鼠物种（1.3%）。在狗狗减数分裂中，基于信号的数量和强度，与二价形成染色体相比，单价染色体显著富集CANR4重复序列。单核苷酸多态性和聚类分析显示，该卫星在狗鼬基因组中具有较高的基因组内同质性。结论CANR4卫星在蔷薇属植物的进化过程中出现较早。它在狗狗基因组中的高含量和非凡的同质性可以解释为它最近在非重组染色体中的扩增。我们推测卫星DNA的扩增可能导致了玫瑰非对称减数分裂中单价染色体的分化。
Abstract Background and Aims Despite their abundant odd-ploidy (2n = 5x = 35), dogroses (Rosa sect. Caninae) are capable of sexual reproduction due to their unique meiosis. During canina meiosis, two sets of chromosomes form bivalents and are transmitted by male and female gametes, whereas the remaining chromosomes form univalents and are exclusively transmitted by the egg cells. Thus, the evolution of chromosomes is expected to be driven by their behaviour during meiosis. Methods To gain insight into differential chromosome evolution, fluorescence in situ hybridization was conducted for mitotic and meiotic chromosomes in four dogroses (two subsections) using satellite and ribosomal DNA probes. By exploiting high-throughput sequencing data, we determined the abundance and diversity of the satellite repeats in the genus Rosa by analysing 20 pentaploid, tetraploid and diploid species in total. Key Results A pericentromeric satellite repeat, CANR4, was found in all members of the genus Rosa, including the basal subgenera Hulthemia and Hesperhodos. The satellite was distributed across multiple chromosomes (5–20 sites per mitotic cell), and its genomic abundance was higher in pentaploid dogroses (2.3 %) than in non-dogrose species (1.3 %). In dogrose meiosis, univalent chromosomes were markedly enriched in CANR4 repeats based on both the number and the intensity of the signals compared to bivalent-forming chromosomes. Single-nucleotide polymorphisms and cluster analysis revealed high intragenomic homogeneity of the satellite in dogrose genomes. Conclusions The CANR4 satellite arose early in the evolution of the genus Rosa. Its high content and extraordinary homogeneity in dogrose genomes is explained by its recent amplification in non-recombining chromosomes. We hypothesize that satellite DNA expansion may contribute to the divergence of univalent chromosomes in Rosa species with non-symmetrical meiosis.