Wolstenholme D R, Macfarlane J L, Okimoto R, Clary D O, Wahleithner J A
Proc Natl Acad Sci U S A. 1987 Mar;84(5):1324-8. doi: 10.1073/pnas.84.5.1324.
The complete nucleotide sequence of the mitochondrial DNA (mtDNA) molecule of the parasitic nematode worm Ascaris suum has been determined. This molecule lacks genes for tRNAs of the standard form. Instead, 21 sequences are found that can be folded into structures that resemble tRNAs in which the T psi C arm and variable loop are missing and replaced with a single loop of between 4 and 12 nucleotides. Considerations of various properties of these sequences, including the number, predicted anticodons, conserved nucleotides, direction of transcription, base composition, and relative gene arrangements are consistent with the interpretation that they are genes for a different sort of tRNA. Transfer RNA genes with a similar potential secondary structure are found in mtDNA of the free-living nematode Caenorhabditis elegans, suggesting that this unusual form of tRNA is used by all nematode mitochondria.
寄生线虫猪蛔虫线粒体DNA（mtDNA）分子的完整核苷酸序列已被确定。该分子缺乏标准形式的tRNA基因。相反，发现了21个序列，它们可以折叠成类似于tRNA的结构，其中TψC臂和可变环缺失，取而代之的是一个由4至12个核苷酸组成的单环。对这些序列的各种特性进行考量，包括数量、预测的反密码子、保守核苷酸、转录方向、碱基组成和相对基因排列，均与它们是不同类型tRNA的基因这一解释相符。在自由生活线虫秀丽隐杆线虫的mtDNA中也发现了具有类似潜在二级结构的tRNA基因，这表明所有线虫线粒体都使用这种不寻常形式的tRNA。
