Abstract：
BACKGROUND: Karyotype dynamics driven by chromosomal rearrangements has long been considered as a fundamental question in the evolutionary genetics. Saccharum spontaneum, the most primitive and complex species in the genus Saccharum, has reportedly undergone at least two major chromosomal rearrangements, however, its karyotypic evolution remains unclear.
RESULTS: In this study, four representative accessions, i.e., hypothetical diploid sugarcane ancestor (sorghum, x = 10), Sa. spontaneum Np-X (x = 10, tetraploid), 2012-46 (x = 9, hexaploid) and AP85-441 (x = 8, tetraploid), were selected for karyotype evolution studies. A set of oligonucleotide (oligo)-based barcode probes was developed based on the sorghum genome, which allowed universal identification of all chromosomes from sorghum and Sa. spontaneum. By comparative FISH assays, we reconstructed the karyotype evolutionary history and discovered that although chromosomal rearrangements resulted in greater variation in relative lengths of some chromosomes, all chromosomes maintained a conserved metacentric structure. Additionally, we found that the barcode oligo probe was not applicable for chromosome identification in both Sa. robustum and Sa. officinarum species, suggesting that sorghum is more distantly related to Sa. robustum and Sa. officinarum compared with Sa. spontaneum species.
CONCLUSIONS: Our study demonstrated that the barcode oligo-FISH is an efficient tool for chromosome identification and karyotyping research, and expanded our understanding of the karyotypic and chromosomal evolution in the genus Saccharum.
RESULTS: In this study, four representative accessions, i.e., hypothetical diploid sugarcane ancestor (sorghum, x = 10), Sa. spontaneum Np-X (x = 10, tetraploid), 2012-46 (x = 9, hexaploid) and AP85-441 (x = 8, tetraploid), were selected for karyotype evolution studies. A set of oligonucleotide (oligo)-based barcode probes was developed based on the sorghum genome, which allowed universal identification of all chromosomes from sorghum and Sa. spontaneum. By comparative FISH assays, we reconstructed the karyotype evolutionary history and discovered that although chromosomal rearrangements resulted in greater variation in relative lengths of some chromosomes, all chromosomes maintained a conserved metacentric structure. Additionally, we found that the barcode oligo probe was not applicable for chromosome identification in both Sa. robustum and Sa. officinarum species, suggesting that sorghum is more distantly related to Sa. robustum and Sa. officinarum compared with Sa. spontaneum species.
CONCLUSIONS: Our study demonstrated that the barcode oligo-FISH is an efficient tool for chromosome identification and karyotyping research, and expanded our understanding of the karyotypic and chromosomal evolution in the genus Saccharum.
摘要：
背景：由染色体重排驱动的核型动力学长期以来一直被认为是进化遗传学中的一个基本问题。糖精,甘蔗属中最原始和最复杂的物种，据报道至少经历了两次主要的染色体重排，然而,其核型进化仍不清楚。
结果：在这项研究中，四个代表加入，即，假设的二倍体甘蔗祖先(高粱，x=10),Sa.自发性Np-X(x=10，四倍体)，2012-46（x=9，六倍体）和AP85-441（x=8，四倍体），被选入核型进化研究。基于高粱基因组开发了一组基于寡核苷酸（寡核苷酸）的条形码探针，它允许对高粱和Sa的所有染色体进行通用鉴定。自发性。通过比较FISH测定，我们重建了核型进化史，发现尽管染色体重排导致了一些染色体相对长度的较大变化，所有染色体都保持保守的亚中心结构。此外,我们发现条形码寡核苷酸探针不适用于两种Sa的染色体鉴定。罗布图姆和萨。铁皮树种，表明高粱与Sa的亲缘关系更远。罗布图姆和萨。与Sa相比。自发性物种。
结论：我们的研究表明，条形码oligo-FISH是染色体鉴定和核型分析研究的有效工具，并扩展了我们对糖属核型和染色体进化的理解。
结果：在这项研究中，四个代表加入，即，假设的二倍体甘蔗祖先(高粱，x=10),Sa.自发性Np-X(x=10，四倍体)，2012-46（x=9，六倍体）和AP85-441（x=8，四倍体），被选入核型进化研究。基于高粱基因组开发了一组基于寡核苷酸（寡核苷酸）的条形码探针，它允许对高粱和Sa的所有染色体进行通用鉴定。自发性。通过比较FISH测定，我们重建了核型进化史，发现尽管染色体重排导致了一些染色体相对长度的较大变化，所有染色体都保持保守的亚中心结构。此外,我们发现条形码寡核苷酸探针不适用于两种Sa的染色体鉴定。罗布图姆和萨。铁皮树种，表明高粱与Sa的亲缘关系更远。罗布图姆和萨。与Sa相比。自发性物种。
结论：我们的研究表明，条形码oligo-FISH是染色体鉴定和核型分析研究的有效工具，并扩展了我们对糖属核型和染色体进化的理解。
