原肌球蛋白在魚類肌肉之結構差異及親緣關係建立

The tropomyosin structure and phylogenetic analysis of five fish species

魚類是脊椎動物中種類及數量最多的生物，具有高度的物種歧異度與生物多樣性，外型相近但不同種類的魚種甚多，在基因及蛋白質上表現多元化，因此魚類之物種鑑定、分類及親緣關係的研究是一個重要的課題。現今物種鑑定及分類研究中常用的分子標記包含粒線體細胞色素b (Cyt b)及細胞色素C氧化酶I (COl)，並非所有的分類及演化皆適用Cyt B及COl系統。本研究想利用原肌球蛋白(TM)發展為分子標記之可能。運動蛋白是一種在演化存在已久之蛋白，其中的原肌球蛋白存在許多生物中，可藉由與肌動蛋白(actin)、肌凝蛋白(myosin)之協調促進肌肉之調節與收縮。本次研究利用原肌球蛋白(tropomyosin)高度保守的特性，以原肌球蛋白之蛋白質及DNA作為分子標記。利用資料庫中已登錄肌肉原肌球蛋白胺基酸及DNA序列之魚類，以計算(calculation)與模擬(simulation)之系統生物學方法，分析白口魚(Pennahiaargentata)、北方黑鮪(Thunnus thynnus)、虎河魨(Takifugu rubripes)、斑馬魚(Danio rerio)、大西洋鮭(Salmo salar)等五種魚類親緣關係的遠近，探討生物原肌球蛋白差異性在演化上之意義。由分析結果發現，原肌球蛋白在五種魚類之DNA、蛋白質一次及二次結構上皆有相異之處，推測與生物功能及適應環境有相當程度的關聯。在建構魚類，演化之親緣關係時發現以原肌球蛋白為標記分子推算出來的結呆比利用Cyt b或COl更接近傳統，演化之理論，代表在魚類演化及親緣關係中，原肌球蛋白是可以被作為分子標記的。本研究希望能利用原肌球蛋白觀點解釋生物演化先後的關係，並作為判斷物種親緣性的新指標。

Fish are vertebrates and the largest number of biological species, they also have high degree of biodiversity. In order to survival in different environments, fish develop many patterns or mechanisms to adapt surrounding changes. For this reason, there are many fishes look similar but not the same species. To identify a correct species is an difficult but important issue for fish science. Today species identification and classification of commonly used molecular markers including mitochondrial cytochrome b and cytochrome c oxidase subunit I. But not all of them are applicable for above systems. This study wanted to use tropomyosin as a new molecular mark ers for fish identification, classification and development. Movement proteins are long-standing presence protein, one of movement proteins, tropomyosin can coordination of regulation and the promotion of muscle contraction with actin and myosin. This study use highly conserved features of tropomyosins as a molecul ar markers by DNA or protein sequences. The use of the logged database of fish muscle tropomyosin amino acid and DNA sequences to calculate and simulation five fish relationship including white croaker (Pennahia argentata ), northern bluefin hula (Thunnus thynnu s), tiger pufferfish (Tnktfugu rnbr ipes), zebrafish (Donio rerio), Atlantic salmon (Salmo salar). We will investigate whether tropomyosin can become a good molecular markers or not. By results, we found the primary and second structure of tropomyosin were different among the five fishes. The various of structure could help the fish with some different biological functions to adapt environment. The results of used tropomyosin as molecular marker to establish phylogenetic tree were more close to traditional theory than used other marker s. This means that tropomyosin can be used as molecular markers for fish evolution and phylogenetic analysis . The study wish to take views to explain the relationship between biological evolution by tropomyosin and a new molecular marker to species identification.