Ekker M, Akimenko M A, Allende M L, Smith R, Drouin G, Langille R M, Weinberg E S, Westerfield M
Department of Medicine, University of Ottawa, Ontario, Canada.
Mol Biol Evol. 1997 Oct;14(10):1008-22. doi: 10.1093/oxfordjournals.molbev.a025707.
The zebrafish genome contains at least five msx homeobox genes, msxA, msxB, msxC, msxD, and the newly isolated msxE. Although these genes share structural features common to all Msx genes, phylogenetic analyses of protein sequences indicate that the msx genes from zebrafish are not orthologous to the Msx1 and Msx2 genes of mammals, birds, and amphibians. The zebrafish msxB and msxC are more closely related to each other and to the mouse Msx3. Similarly, although the combinatorial expression of the zebrafish msx genes in the embryonic dorsal neuroectoderm, visceral arches, fins, and sensory organs suggests functional similarities with the Msx genes of other vertebrates, differences in the expression patterns preclude precise assignment of orthological relationships. Distinct duplication events may have given rise to the msx genes of modern fish and other vertebrate lineages whereas many aspects of msx gene functions during embryonic development have been preserved.
斑马鱼基因组至少包含五个msx同源框基因，即msxA、msxB、msxC、msxD以及新分离出的msxE。尽管这些基因具有所有Msx基因共有的结构特征，但蛋白质序列的系统发育分析表明，斑马鱼的msx基因与哺乳动物、鸟类和两栖动物的Msx1和Msx2基因并非直系同源。斑马鱼的msxB和msxC彼此之间以及与小鼠的Msx3关系更为密切。同样，尽管斑马鱼msx基因在胚胎背侧神经外胚层、内脏弓、鳍和感觉器官中的组合表达表明其与其他脊椎动物的Msx基因在功能上有相似之处，但表达模式的差异排除了直系同源关系的精确确定。不同的复制事件可能导致了现代鱼类和其他脊椎动物谱系中msx基因的产生，而msx基因在胚胎发育过程中的许多功能方面得以保留。
