Molecular Phylogeny of the Sacoglossa, With a Discussion of Gain and Loss of Kleptoplasty in the Evolution of the Group
Molecular Phylogeny of the Sacoglossa, With a Discussion of Gain and Loss of Kleptoplasty in the Evolution of the Group
复制标题
DOI：
10.1086/bblv219n1p17
复制
发表时间：
2010-08
期刊：
影响因子：
--
通讯作者：
T. Maeda;T. Kajita;T. Maruyama;Y. Hirano
中科院分区：
文献类型：
--
作者：
T. Maeda;T. Kajita;T. Maruyama;Y. Hirano
Sacoglossan海参将食用藻中的叶绿体保留在其细胞中(Kleupplants)，并获得光合作用产物，但kleupplit的能力因物种而异。关于扁桃体成形术的一种进化论假说是，弓形科是出现扁桃体成形术的骶舌系祖先，但这是建立在模糊的系统发育关系基础上的。为了验证这一假说，我们使用邻接法、最大简约法、最大似然法和贝叶斯方法分析了18个sacoglossan物种的核(18S RRNA)和线粒体(CO1、trnV和16S rRNA)基因的串联序列(约4000 bp)的系统发育。由此产生的系统发育树清楚地揭示了Sacoglossa目(包括有争议的Cylindroblla属)的单系，它包含两个姊妹支系：有壳的Sacoglossa组(棘藻科+CylindroBulla)和无壳的组(Plakobranchacea)。该科在棘藻科中处于派生地位。在系统发育树上最简约的重排表明：(1)在Sacoglossa(包括柱状大泡)的基底部获得的是无功能的成形术，(2)在Plkobranchacea支系获得了功能性的Klepreplit，(3)在Oxynoacea的Volvatellidae分支中失去了无功能的Klepreplit。
Sacoglossan sea slugs retain the chloroplasts from food algae in their cells (kleptoplasty) and obtain the photosynthetic products, but the capability of kleptoplasty differs among species. One evolutionary hypothesis for kleptoplasty is that the family Volvatellidae is the ancestral sacoglossan lineage in which kleptoplasty arose, but this is based on ambiguous phylogenetic relationships. To test this hypothesis, we analyzed sacoglossan phylogeny for concatenated sequences (approximately 4000 bp) of nuclear (18S rRNA) and mitochondrial (CO1, trnV, and 16S rRNA) genes of 18 sacoglossan species, using neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian methods. The resultant phylogenetic trees clearly revealed monophyly of the order Sacoglossa (including the debatable genus Cylindrobulla), which contained two sister clades: the shelled sacoglossan group (Oxynoacea + Cylindrobulla) and the non-shelled group (Plakobranchacea). The family Volvatellidae was in a derived position within the Oxynoacea. The most parsimonious rearrangement of the character states of kleptoplasty on the phylogenetic tree suggested that (1) kleptoplasty was acquired at the basal position of the Sacoglossa (including Cylindrobulla) as non-functional kleptoplasty, (2) functional kleptoplasty was gained in the Plakobranchacea clade, and (3) non-functional kleptoplasty was lost in the Volvatellidae lineage in the Oxynoacea clade.