細胞生物学研究系・細胞情報研究部門の寺井洋平研究員、岡田典弘教授らはゼブラフィッシュの体表模様変異体より単離されたhagoromo(hag)遺伝子がカワスズメ科魚類で複雑な選択的スプライシングを受けていることを示し、この選択的スプライシングのパターンと種分化の頻度に関連があることを明らかにしました。この結果は米国の科学雑誌「Proceedings of the National Academy of Sciences of the United States of America」の10月号に掲載されました（online版は2004年10月20日）。

発刊及びナンバー：2004年10月28日号 第100巻 12798-12803頁
論文タイトル：The complexity of alternative splicing of hagoromo mRNAs is increased in an explosively speciated lineage in East African cichlids.

論文著者：Yohey Terai, Naoko Morikawa, Koichi Kawakami, and Norihiro Okada.

The adaptive radiation of cichlid fishes in the lakes of East Africa is a prime example of speciation. The choice of cichlid mates based on a variety of coloration represents a potential basis for speciation that led to the adaptive radiation. Here, we characterize the cichlid homolog of the zebrafish hagoromo (hag) gene that was recently cloned and characterized from a pigmentation mutant. Although only one hag mRNA was reported in zebrafish, cichlids express nine different hag mRNAs resulting from alternative splicing. The hag mRNAs are expressed between the myotome and the epidermis where pigment cells are located, suggesting the cichlid hag gene is involved in pigmentation. The hag mRNA splicing pattern does not fluctuate among individuals from each of two species suggesting that alternative splice site choice is fixed within species. Furthermore, cichlids in lineages that underwent explosive speciation expressed a greater variety of hag mRNAs than those in lineages that did not undergo such a degree of speciation, suggesting that species in the explosively speciated lineage acquired a complex regulatory mechanism of alternative splicing over a very short evolutionary period. Here, we provide an example in which alternative splicing may play a role in mate choice leading to cichlid speciation through diversification of gene function via production of multiple mRNAs from a single gene.