Comparisons with Caenorhabditis (∼100 Mb) and Drosophila (∼175 Mb) using flow cytometry show genome size in Arabidopsis to be ∼157 Mb and thus ∼25 % larger than the Arabidopsis genome initiative estimate of ∼125 Mb
Comparisons with Caenorhabditis (∼100 Mb) and Drosophila (∼175 Mb) using flow cytometry show genome size in Arabidopsis to be ∼157 Mb and thus ∼25 % larger than the Arabidopsis genome initiative estimate of ∼125 Mb
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DOI：
10.1093/aob/mcg057
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发表时间：
2003-04-01
期刊：
影响因子：
4.2
通讯作者：
Johnston, JS
中科院分区：
文献类型：
--
作者：
Bennett, MD;Leitch, IJ;Johnston, JS
近期的基因组测序论文给出了黑腹果蝇Iso - 1的基因组大小为1.8亿碱基对，拟南芥哥伦比亚生态型为1.25亿碱基对。前者与早期的细胞化学估计相符，但众多约1.7亿碱基对的细胞计量估计表明，拟南芥1.25亿碱基对的基因组大小被低估了。在这项研究中，使用流式细胞术直接比较了物种对的细胞核。同时检测的哥伦比亚生态型拟南芥和Iso - 1果蝇的雌性个体，拟南芥的2C峰仅比果蝇的低约15%，并且16C的哥伦比亚生态型内多倍体细胞核的DNA比2C的鸡细胞核（大于等于22.8亿碱基对）多约15%。秀丽隐杆线虫布里斯托尔N2品系（基因组大小约1亿碱基对）与哥伦比亚生态型拟南芥或Iso - 1果蝇同时检测，果蝇的2C峰比秀丽隐杆线虫的2C峰高约75%，拟南芥的2C峰比秀丽隐杆线虫的高约57%。这证实了果蝇的1C约为1.75亿碱基对，并且结合其他证据，我们得出结论：拟南芥的基因组大小不是约1.25亿碱基对，而可能是约1.57亿碱基对。这种差异可能代表着异染色质区域未测序间隙中的额外重复序列。仍然需要对拟南芥基因组进行完全测序，直到在端粒、核仁组织区或着丝粒处没有间隙，以便提供第一个精确的被子植物C值作为植物基因组的基准校准标准，并确保在拟南芥中没有遗漏基因，特别是在着丝粒区域，其显然比曾经想象的要大。（C）2003年植物学年鉴公司
Recent genome sequencing papers have given genome sizes of 180 Mb for Drosophila melanogaster Iso-1 and 125 Mb for Arabidopsis thaliana Columbia. The former agrees with early cytochemical estimates, but numerous cytometric estimates of around 170 Mb imply that a genome size of 125 Mb for arabidopsis is an underestimate. In this study, nuclei of species pairs were compared directly using flow cytometry. Co-run Columbia and Iso-1 female gave a 2C peak for arabidopsis only approx. 15 % below that for drosophila, and 16C endopolyploid Columbia nuclei had approx. 15 % more DNA than 2C chicken nuclei (with greater than or equal to2280 Mb). Caenorhabditis elegans Bristol N2 (genome size approx. 100 Mb) co-run with Columbia or Iso-1 gave a 2C peak for drosophila approx. 75 % above that for 2C C. elegans, and a 2C peak for arabidopsis approx. 57 % above that for C. elegans. This confirms that 1C in drosophila is approx. 175 Mb and, combined with other evidence, leads us to conclude that the genome size of arabidopsis is not approx. 125 Mb, but probably approx. 157 Mb. It is likely that the discrepancy represents extra repeated sequences in unsequenced gaps in heterochromatic regions. Complete sequencing of the arabidopsis genome until no gaps remain at telomeres, nucleolar organizing regions or centromeres is still needed to provide the first precise angiosperm C-value as a benchmark calibration standard for plant genomes, and to ensure that no genes have been missed in arabidopsis, especially in centromeric regions, which are clearly larger than once imagined. (C) 2003 Annals of Botany Company.