Lamb T, Lydeard C
Department of Biology, East Carolina University, Greenville, North Carolina 27858.
Mol Phylogenet Evol. 1994 Dec;3(4):283-91. doi: 10.1006/mpev.1994.1036.
Sequences from the mitochondrial cytochrome b gene were obtained to examine molecular phylogenetic relationships among the North American gopher tortoises. Data from 352 aligned positions generated a single most-parsimonious tree for each of three analytical approaches: (1) equal weighting, all substitutions; (2) equal weighting, third position changes limited to transversions; and (3) transversions weighted 10 times transitions. Identical topologies for the resulting trees depict the gopher tortoises as a monophyletic group comprising two well-defined clades. Observed sequence divergence (7.0%) between the agassizii (Gopherus agassizii; G. berlandieri) and the polyphemus (G. flavomarginatus; G. polyphemus) clades suggests an Early Miocene separation of these lineages. The cytochrome b phylogeny complements some previous systematic interpretations, including formal taxonomic recognition of the two distinct groups, but is at odds with the most recent morphological analysis. Additional sequence comparisons of selected testudinoid (batagurid, emydid, and testudinid) taxa yielded a phylogeny consistent with a morphologically based hypothesis demonstrating close phylogenetic affinities between the Testudinidae and the "Bataguridae."
获得了线粒体细胞色素b基因的序列，以研究北美穴居陆龟之间的分子系统发育关系。来自352个比对位置的数据为三种分析方法中的每一种生成了一棵单一的最简约树：(1) 同等加权，所有替换；(2) 同等加权，第三位变化限于颠换；(3) 颠换加权为转换的10倍。所得树的相同拓扑结构将穴居陆龟描绘为一个单系群，由两个定义明确的分支组成。在阿加西氏穴居陆龟（Gopherus agassizii；G. berlandieri）分支和多芬氏穴居陆龟（G. flavomarginatus；G. polyphemus）分支之间观察到的序列差异（百分之7.0）表明这些谱系在中新世早期就已分离。细胞色素b系统发育补充了一些先前的系统解释，包括对这两个不同群体的正式分类学认可，但与最近的形态学分析不一致。对选定的龟鳖类（地龟科、水龟科和陆龟科）类群进行的额外序列比较产生了一个与基于形态学的假设一致的系统发育，该假设表明陆龟科和“地龟科”之间存在密切的系统发育亲缘关系。
