Evolution of echinoderms may not have required modification of the ancestral deuterostome HOX gene cluster: first report of PG4 and PG5 Hox orthologues in echinoderms
Evolution of echinoderms may not have required modification of the ancestral deuterostome HOX gene cluster: first report of PG4 and PG5 Hox orthologues in echinoderms
复制标题
棘皮动物的进化可能不需要修改祖先后口动物 HOX 基因簇：棘皮动物中 PG4 和 PG5 Hox 直向同源物的首次报告
DOI：
10.1007/s00427-003-0355-3
复制
发表时间：
2003
影响因子：
2.4
通讯作者：
M. Byrne
中科院分区：
文献类型：
--
作者：
S. Long;P. Martinez;Wei;M. Thorndyke;M. Byrne
棘皮动物体型的极端衍生是否反映在衍生的棘皮动物Hox基因型中？在以前工作的基础上，我们利用同源框的序列保守性，从两个小行星棘皮动物中分离出几个Hox基因的推定直系同源物。5-肽基序（LPNTK）诊断PG 4 Hox基因的下游立即确定的部分同源结构域从甜菜夜蛾。这构成了第一个明确的报告PG 4 Hox基因直系同源物从棘皮动物。随后的筛选鉴定了红阿斯特里亚斯中PG 4和PG 4/5的基因。虽然在棘皮动物只有一个基因（PG 4/5）占据这两个连续的集群位置，我们得出结论，祖先棘皮动物必须有完整的后口套内侧Hox基因，包括直向同源的PG 4和PG 4/5（= PG 5）。因此，在棘皮动物的HOX簇中没有PG 4的报道是一种衍生状态，并且祖先棘皮动物可能具有与其他后口动物相似的HOX簇。修改祖先的后口类Hox基因型可能并不需要进化的高度衍生棘皮动物的身体计划。
Is the extreme derivation of the echinoderm body plan reflected in a derived echinoderm Hox genotype? Building on previous work, we exploited the sequence conservation of the homeobox to isolate putative orthologues of several Hox genes from two asteroid echinoderms. The 5-peptide motif (LPNTK) diagnostic of PG4 Hox genes was identified immediately downstream of one of the partial homeodomains from Patiriella exigua. This constitutes the first unequivocal report of a PG4 Hox gene orthologue from an echinoderm. Subsequent screenings identified genes of both PG4 and PG4/5 in Asterias rubens. Although in echinoids only a single gene (PG4/5) occupies these two contiguous cluster positions, we conclude that the ancestral echinoderm must have had the complete deuterostome suite of medial Hox genes, including orthologues of both PG4 and PG4/5 (= PG5). The reported absence of PG4 in the HOX cluster of echinoids is therefore a derived state, and the ancestral echinoderm probably had a HOX cluster not dissimilar to that of other deuterostomes. Modification of the ancestral deuterostome Hox genotype may not have been required for evolution of the highly derived echinoderm body plan.