The molecular evolution of spiggin nesting glue in sticklebacks.
The molecular evolution of spiggin nesting glue in sticklebacks.
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DOI：
10.1111/mec.13317
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发表时间：
2015-09
影响因子：
4.9
通讯作者：
Barber I
中科院分区：
文献类型：
--
作者：
Seear PJ;Rosato E;Goodall-Copestake WP;Barber I
基因复制和随后的分化可以导致新功能和谱系特异性特征的进化。在棘鱼中，黏液蛋白基因（MUC19）的连续复制成为串联排列的多基因家族，使得大量的“黏液蛋白”（spiggin）得以产生，这是一种分泌的黏附蛋白，对筑巢至关重要。本文研究了三刺棘鱼（Gasterosteus aculeatus）的spiggin基因差异，并提出了基因复制的基本机制。Sanger测序揭示了spiggin转录本的大量多样性，包括选择性剪接变体和染色体间spiggin嵌合基因。将测序的转录本与所有其他公共领域的spiggin基因进行比较分析，支持存在三个主要的spiggin谱系（spiggin A， spiggin B和spiggin C），并进一步细分为spiggin B （B1, B2）和spiggin C （C1, C2）。Spiggin A与祖先MUC19的差异最小，而Spiggin C重复序列的差异最大。spiggin基因开放阅读框的计算机翻译预测，spiggins A和B以长黏液蛋白样聚合物的形式分泌，而spiggins C1和C2以短单体的形式分泌，具有推测的抗菌特性。我们认为，重复的spiggin基因的多样化促进了spiggin对一系列水生栖息地的局部适应。
Gene duplication and subsequent divergence can lead to the evolution of new functions and lineage‐specific traits. In sticklebacks, the successive duplication of a mucin gene (MUC19) into a tandemly arrayed, multigene family has enabled the production of copious amounts of ‘spiggin’, a secreted adhesive protein essential for nest construction. Here, we examine divergence between spiggin genes among three‐spined sticklebacks (Gasterosteus aculeatus) from ancestral marine and derived freshwater populations, and propose underpinning gene duplication mechanisms. Sanger sequencing revealed substantial diversity among spiggin transcripts, including alternatively spliced variants and interchromosomal spiggin chimeric genes. Comparative analysis of the sequenced transcripts and all other spiggin genes in the public domain support the presence of three main spiggin lineages (spiggin A, spiggin B and spiggin C) with further subdivisions within spiggin B (B1, B2) and spiggin C (C1, C2). Spiggin A had diverged least from the ancestral MUC19, while the spiggin C duplicates had diversified most substantially. In silico translations of the spiggin gene open reading frames predicted that spiggins A and B are secreted as long mucin‐like polymers, while spiggins C1 and C2 are secreted as short monomers, with putative antimicrobial properties. We propose that diversification of duplicated spiggin genes has facilitated local adaptation of spiggin to a range of aquatic habitats.