Seixas Victor Corrêa, Russo Claudia Augusta de Moraes, Paiva Paulo Cesar
Universidade Federal do Rio de Janeiro, CCS, Instituto de Biologia, Departamento de Genética, Av. Carlos Chagas Filho 373, Sala A2-97, Bloco A, Ilha do Fundão, Rio de Janeiro, RJ 21941-570, Brazil.
Universidade Federal do Rio de Janeiro, CCS, Instituto de Biologia, Departamento de Genética, Av. Carlos Chagas Filho 373, Sala A2-97, Bloco A, Ilha do Fundão, Rio de Janeiro, RJ 21941-570, Brazil.
Gene. 2017 Mar 20;605:43-53. doi: 10.1016/j.gene.2016.12.024. Epub 2016 Dec 26.
Here we describe, for the first time, the mitochondrial genome of Spirobranchus giganteus (Annelida: Serpulidae) and compare it with all available annelid mitogenomes. The entire mitogenome has 22,058bp in length and bears 12 protein-coding genes (the ATP8 gene is missing), two rRNA, and 24 tRNA genes. The nucleotide composition and GC-skew are surprisingly different from those reported for other annelids. In addition, the pairwise genetic distances between the mitogenomes of S. giganteus and other annelids are higher than the distances for all annelid taxa analyzed. This result is consistent with a faster rate of mitochondrial sequence evolution in S. giganteus, which may explain the difficulty in obtaining PCR products with the available primers. The mitochondrial gene order of S. giganteus was remarkably different not only from that of the Sedentaria lineage, which includes S. giganteus, but also from the mitochondrial gene order of other major annelid lineages. The mitogenome of S. giganteus has no repetitive motifs despite its long control region (4769bp), but genes are shorter and have a lower AT content than other members of Annelida. Finally, we show that mitochondrial gene order rearrangements can directly correlate to variations in gene length.
在此，我们首次描述了大旋鳃虫（环节动物门：龙介虫科）的线粒体基因组，并将其与所有已有的环节动物线粒体基因组进行比较。整个线粒体基因组长度为22,058bp，包含12个蛋白质编码基因（缺少ATP8基因）、两个rRNA基因和24个tRNA基因。其核苷酸组成和GC偏斜与其他环节动物报道的情况惊人地不同。此外，大旋鳃虫线粒体基因组与其他环节动物线粒体基因组之间的成对遗传距离高于所有分析的环节动物类群的距离。这一结果与大旋鳃虫线粒体序列进化速度较快一致，这可能解释了使用现有引物获得PCR产物的困难。大旋鳃虫的线粒体基因排列不仅与包括大旋鳃虫在内的定居亚纲谱系的排列显著不同，也与其他主要环节动物谱系的线粒体基因排列不同。尽管大旋鳃虫的控制区较长（4769bp），但其线粒体基因组没有重复基序，但其基因较短，且AT含量低于环节动物门的其他成员。最后，我们表明线粒体基因排列重排可直接与基因长度的变化相关。
