Telomeres are structures enriched in repetitive sequences at the end of chromosomes. In this study, using the telomere primer AA(CCCTAAA)3CCC for the single primer PCR, two DNA sequences were obtained from Gossypium hirsutum (Linnaeus, 1753) accession (acc.) TM-1. Sequence analysis showed that the two obtained sequences were all rich in A/T base, which was consistent with the characteristic of the telomere-associated sequence (TAS). They were designated as GhTAS1 and GhTAS2 respectively. GhTAS1 is 489 bp long, with 57.6% of A/T, and GhTAS2 is 539 bp long, with 63.9% of A/T. Fluorescence in situ hybridization results showed that both of the cloned TASs were located at the ends of the partial chromosomes of G. hirsutum, with the strong signals, which further confirmed that GhTAS1 and GhTAS2 were telomere-associated sequences including highly tandemly repetitive sequences. Results of blast against the assembled genome of G. hirsutum showed that GhTAS sequences may be missed on some assembled chromosomes. The results provide important evidence for the evaluation of the integrity of assembled chromosome end sequences, and will also contribute to the further perfection of the draft genomes of cotton.

中文翻译：

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陆地棉端粒相关序列的克隆和初步验证。

端粒是在染色体末端富含重复序列的结构。在这项研究中，使用端粒引物AA（CCCTAAA）3CCC进行单引物PCR，从陆地棉（Linnaeus，1753）登录号（acc。）TM-1获得了两个DNA序列。序列分析表明，获得的两个序列均富含A / T碱基，这与端粒相关序列（TAS）的特征一致。它们分别指定为GhTAS1和GhTAS2。GhTAS1长489 bp，占A / T的57.6％，GhTAS2长539 bp，占A / T的63.9％。荧光原位杂交结果表明，两个克隆的TAS均位于G. hirsutum部分染色体的末端，具有较强的信号，进一步证实GhTAS1和GhTAS2是端粒相关序列，包括高度串联的重复序列。对hir.tum的组装基因组进行原始鉴定的结果表明，在一些组装的染色体上可能缺少GhTAS序列。该结果为评估组装的染色体末端序列的完整性提供了重要的证据，还将有助于棉花棉花基因组草案的进一步完善。