She Chao-Wen, Mao Ying, Jiang Xiang-Hui, He Chun-Ping
Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province, Huaihua University, Huaihua, Hunan, 418008, China Huaihua University Huaihua China.
Key Laboratory of Xiangxi Medicinal Plant and Ethnobotany of Hunan Higher Education, Huaihua University, Huaihua, Hunan, 418008, China Huaihua University Huaihua China.
Comp Cytogenet. 2020 Jun 26;14(2):243-264. doi: 10.3897/CompCytogen.v14i2.51154. eCollection 2020.
To extend our knowledge on karyotype variation of the genus Savi, 1824, the chromosomal organization of rRNA genes and fluorochrome banding patterns of five wild species were studied. Sequential combined PI (propidium iodide) and DAPI (4',6-diamidino-2-phenylindole) (CPD) staining and fluorescence hybridization (FISH) with 5S and 45S rDNA probes were used to analyze the karyotypes of (Jacquin, 1771) Bentham, 1959, (Linnaeus, 1753) A. Richard, 1845, (Roxburgh, 1832) Ohwi & H. Ohashi, 1969, (Linnaeus, 1753) Verdcourt, 1968, and (Linnaeus, 1753) Verdcourt,1970. For further phylogenetic analysis, genomic hybridization (GISH) with the genomic DNA of (Thunberg, 1794) Ohwi & H.Ohashi, 1969 onto the chromosomes of five wild species was also performed. Detailed karyotypes were established for the first time using chromosome measurements, fluorochrome bands, and rDNA-FISH signals. All species had chromosome number 2n = 2x = 22, and symmetrical karyotypes that composed of only metacentric or metacentric and submetacentric chromosomes. CPD staining revealed all 45S rDNA sites in the five species analyzed, (peri)centromeric GC-rich heterochromatin in , and , interstitial GC-rich and pericentromeric AT-rich heterochromatin in . rDNA-FISH revealed two 5S loci in and one 5S locus in the other four species; one 45S locus in and , two 45S loci in and , and five 45S loci in . The karyotypes of the studied species could be clearly distinguished by the karyotypic parameters, and the patterns of the fluorochrome bands and the rDNA sites, which revealed high interspecific variation among the five species. The genomic DNA probe produced weak signals in all proximal regions of and all (peri)centromeric regions of . The combined data demonstrate that distinct genome differentiation has occurred among the five species during evolution. The phylogenetic relationships between the five wild species and related cultivated species of are discussed based on our present and previous molecular cytogenetic data.
为了拓展我们对1824年萨维属核型变异的认识，研究了5个野生物种的rRNA基因的染色体组织和荧光带型。采用碘化丙啶（PI）和4',6-二脒基-2-苯基吲哚（DAPI）顺序联合染色（CPD）以及用5S和45S rDNA探针进行荧光原位杂交（FISH）来分析（雅克金，1771年）边沁，1959年、（林奈，1753年）A. 理查德，1845年、（罗克斯堡，1832年）大井和大桥，1969年、（林奈，1753年）弗德科特，1968年以及（林奈，1753年）弗德科特，1970年的核型。为了进行进一步的系统发育分析，还对5个野生物种的染色体进行了以（桑伯格，1794年）大井和大桥，1969年的基因组DNA为探针的基因组原位杂交（GISH）。首次利用染色体测量、荧光带和rDNA-FISH信号建立了详细的核型。所有物种的染色体数目均为2n = 2x = 22，且核型对称，仅由中着丝粒染色体或中着丝粒染色体和亚中着丝粒染色体组成。CPD染色揭示了所分析的5个物种中的所有45S rDNA位点，在[物种名1]、[物种名2]和[物种名3]中有（近）着丝粒富含GC的异染色质，在[物种名4]中有居间富含GC和着丝粒周围富含AT的异染色质。rDNA-FISH显示[物种名1]中有两个5S位点，其他4个物种中有一个5S位点；[物种名1]和[物种名2]中有一个45S位点，[物种名3]和[物种名4]中有两个45S位点，[物种名5]中有五个45S位点。所研究物种的核型可通过核型参数、荧光带型和rDNA位点模式清楚地区分，这揭示了这5个物种之间存在高度的种间变异。基因组DNA探针在[物种名1]的所有近端区域和[物种名2]的所有（近）着丝粒区域产生微弱信号。综合数据表明，在进化过程中这5个物种之间发生了明显的基因组分化。基于我们目前和以前的分子细胞遗传学数据，讨论了这5个野生物种与相关栽培物种之间的系统发育关系。
