Zapata Felipe, Wilson Nerida G, Howison Mark, Andrade Sónia C S, Jörger Katharina M, Schrödl Michael, Goetz Freya E, Giribet Gonzalo, Dunn Casey W
Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02906, USA
Western Australian Museum, Welshpool, WA 6106, Australia.
Proc Biol Sci. 2014 Nov 7;281(1794):20141739. doi: 10.1098/rspb.2014.1739.
Gastropods are a highly diverse clade of molluscs that includes many familiar animals, such as limpets, snails, slugs and sea slugs. It is one of the most abundant groups of animals in the sea and the only molluscan lineage that has successfully colonized land. Yet the relationships among and within its constituent clades have remained in flux for over a century of morphological, anatomical and molecular study. Here, we re-evaluate gastropod phylogenetic relationships by collecting new transcriptome data for 40 species and analysing them in combination with publicly available genomes and transcriptomes. Our datasets include all five main gastropod clades: Patellogastropoda, Vetigastropoda, Neritimorpha, Caenogastropoda and Heterobranchia. We use two different methods to assign orthology, subsample each of these matrices into three increasingly dense subsets, and analyse all six of these supermatrices with two different models of molecular evolution. All 12 analyses yield the same unrooted network connecting the five major gastropod lineages. This reduces deep gastropod phylogeny to three alternative rooting hypotheses. These results reject the prevalent hypothesis of gastropod phylogeny, Orthogastropoda. Our dated tree is congruent with a possible end-Permian recovery of some gastropod clades, namely Caenogastropoda and some Heterobranchia subclades.
腹足纲动物是软体动物中一个高度多样化的进化枝，包含许多常见的动物，如帽贝、蜗牛、蛞蝓和海蛞蝓。它是海洋中数量最多的动物群体之一，也是唯一成功在陆地上定殖的软体动物谱系。然而，在超过一个世纪的形态学、解剖学和分子研究中，其组成进化枝之间以及内部的关系一直处于变化之中。在这里，我们通过收集40个物种的新转录组数据，并将它们与公开可用的基因组和转录组结合分析，重新评估腹足纲动物的系统发育关系。我们的数据集包括腹足纲动物的所有五个主要进化枝：笠形腹足亚纲、古腹足亚纲、新腹足目、前鳃亚纲和异鳃亚纲。我们使用两种不同的方法来确定直系同源关系，将每个矩阵抽样为三个密度逐渐增加的子集，并使用两种不同的分子进化模型分析所有这六个超级矩阵。所有12项分析都得出了连接五个主要腹足纲动物谱系的相同无根网络。这将腹足纲动物的深层系统发育简化为三种替代的生根假设。这些结果否定了腹足纲动物系统发育的普遍假设，即正腹足目。我们的定年树与一些腹足纲动物进化枝（即前鳃亚纲和一些异鳃亚纲分支）可能在二叠纪末期复苏的情况一致。
