The mtDNA sequence of the ostrich and the divergence between paleognathous and neognathous birds
The mtDNA sequence of the ostrich and the divergence between paleognathous and neognathous birds
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DOI：
10.1093/oxfordjournals.molbev.a025815
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发表时间：
1997-07-01
影响因子：
10.7
通讯作者：
Arnason, U
中科院分区：
文献类型：
--
作者：
Harlid, A;Janke, A;Arnason, U
测定了鸵鸟（Struthio camelus）线粒体DNA全序列。该分子的大小为16，591个核苷酸。由于鸵鸟代表了古颚类鸟类，与迄今为止在数据库中报道的唯一鸟类物种新颚鸡的mtDNA进行比较，可以识别常见的，可能是一般的鸟类mtDNA特征。相对于其他脊椎动物，禽类的NADH 6和tRNA-Glu基因位于控制区的上游，而不是细胞色素B基因。鸵鸟的NADH 3基因由207位的终止密码子终止。因此，该基因比其他脊椎动物短约130个核苷酸。两种鸟的L链复制起点序列均缺失，两种鸟mtDNA的四个转运RNA基因偏离了脊椎动物mtDNA转运RNA的共同特征，在第8位有一个腺嘌呤（而不是胸苷）。由于缺乏合适的化石，大多数鸟类分歧的古生物学定年是化石。鸵鸟和鸡之间分歧的分子年代测定表明，这两个鸟类谱系分离了80-90百万年。完整的细胞色素B基因的6个鸟类订单的系统发育分析表明，雀形目代表最近的鸟类之间最早的分歧，矛盾的普遍接受的概念之间的基础位置的古颚最近的鸟类。
The complete mitochondrial DNA (mtDNA) molecule of the ostrich, Struthio camelus, was sequenced. The size of the molecule is 16,591 nucleotides. Since the ostrich represents the paleognathous birds, comparison with the mtDNA of the neognathous chicken, the only avian species reported so far in databases, made it possible to identify common and, probably, general avian mtDNA characteristics. Relative to other vertebrates, the avian NADH6 and tRNA-Glu genes are positioned upstream of the control region rather than the cytochrome b gene. The NADH3 gene of the ostrich is terminated by a stop codon at position 207. Thus, the gene is about 130 nucleotides shorter than in other vertebrates. The sequence for L-strand origin of replication is missing in both birds, and four transfer RNA genes of the two avian mtDNAs deviate from common characteristics of tRNAs of vertebrate mtDNAs by having an adenine (and not a thymidine) at position 8. Due to the absence of suitable fossils, most paleontological datings of avian divergences are conjectural. Molecular dating of the divergence between the ostrich and the chicken indicates that these two avian lineages separated 80-90 MYA. Phylogenetic analysis of complete cytochrome b genes of six avian orders showed that Passeriformes represent the earliest divergence among recent birds, contradicting the commonly accepted notion of a basal position of the Palaeognathae among recent birds.