斑马鱼不仅是实验室常用的模式动物，而且是一种小型热带观赏鱼，具有黑色和黄色条纹，它的条纹是由黑色和黄色色素细胞组成，但是同类色素细胞为何能集合在一起形成花纹？近日，日本一项新研究探明了其原理。相关论文发表在2月10日的Science杂志上。
大阪大学一个研究小组报告说，斑马鱼体内两种颜色的色素细胞会互相排斥，而同色的色素细胞则更容易相互吸附，这样的移动对于花纹的形成起到重要作用。
此次研究中，研究人员从斑马鱼体内取出这两种色素细胞，放到培养皿中观察。结果发现，如果是条纹非常清晰的斑马鱼，它的黄色色素细胞接触到黑色色素细胞瞬间，黑色色素细胞会立即“逃”向相反方向。
这是由于两种细胞接触后，细胞膜的电性发生变化，产生了排斥反应。而相同颜色的色素细胞则容易吸附在一起。由于不断重复这一过程，色素细胞根据不同颜色分别聚集，从而形成了花纹。但条纹不鲜明的变异个体，它的色素细胞就不会发生这种反应，黑色和黄色的细胞会一直混合在一起。
研究人员说，其他动物的花纹形成原理应该也与此类似，今后他们将进一步研究动物花纹形成的普遍原理。（生物谷Bioon.com）
doi:10.1126/science.1212821
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Pigment Pattern Formation by Contact-Dependent Depolarization
Masafumi Inaba, Hiroaki Yamanaka, Shigeru Kondo
Although recent experimental studies have suggested that the interactions among the pigment cells play a key role in the skin pattern formation, details of the mechanism remain largely unknown. By using an in vitro cell culture system, we have detected interactions between the two pigment cell types, melanophores and xanthophores, in the zebrafish skin. During primary culture, the melanophore membrane transiently depolarizes when contacted with the dendrites of a xanthophore. This depolarization triggers melanophore migration to avoid further contact with the xanthophores. Cell depolarization and repulsive movement were not observed in pigment cells with the jaguar mutant, which shows defective segregation of melanophores and xanthophores. The depolarization-repulsion of wild-type pigment cells may explain the pigment cell behaviors generating the stripe pattern of zebrafish.
