在人類基因體定序工作接近尾聲之同時，許多模式生物的序列與基因數目也陸續地被決定出來。其中人類基因數目出乎生物學家預料的僅在30,000到40,000個之間。此時生物學家們所共同發出的疑問是，人類是如何以僅有線蟲或果蠅不到兩倍的基因數目呈現出如此複雜的生物型態？而比起線蟲來說要複雜數倍的果蠅其基因數目又為何反而比線蟲要來得少？從人類表現序列（EST sequences）與基因體序列比對的結果顯示，在高等生物中基因普遍會發生多元性剪接作用以增加其基因表現的複雜度，其發生機率估計約在35﹪─59﹪左右。在本論文中我們以人類ArfGAP基因家族作為研究對象，希望能藉由它們幫助我們實際瞭解在人體中基因是如何以多元性剪接的方式增加其蛋白質表現的複雜度。我們研究的方法是，先採用生物資訊學的軟體比對公用資料庫中的基因或蛋白質序列後進行預測、篩選與分析的工作，接著以RT-PCR的方式驗證預測結果。由實驗結果估計人類ArfGAP基因家族多元性剪接發生機率約在37.5﹪左右，並且其可經由不同排列組合的剪接形式表現出更多元化的等形蛋白質序列。另外在實驗過程中經由比對基因在正常成人及胎兒肝臟，以及在肝癌病人組織中的表現情形，意外地發現到一個有潛力發展為肝癌標誌的基因“KIAA1099”，並在未來將對其進行更深入的探討。

Since the beginning of the human genome project in 1990, genome sequences of many model organisms have been determined one after another. The reports of only 30,000 to 40,000 genes in the human genome came as a surprise. How could the human’s genome have only approximately twice as many gene as the relatively simple organisms, e.g. Caenorhabditis elegans and Drosophila melanogaster ? How could the fly genome contain fewer genes than the less complex organism - worm ? Depending on the alignment of human EST sequences to genomic sequence, biologists have estimated that, comparing to the fly and worm, the frequency of alternative splicing in the human genome is rather high at about 35─59﹪. In our study, we used the human ArfGAP gene family as a model to examine the roles of alternative splicing in generating protein diversity. According to the results, the alternative splicing frequency of the human ArfGAP gene family is about 37.5﹪and it may be still an underestimate. Furthermore, we found that one gene (KIAA1099) may adopt combinatorial alternative splicing to produce more complex isoforms. Meanwhile, the KIAA1099 gene may be a potential liver cancer marker gene by comparative analysis of its expression patterns in normal adult and fetal livers, and hepatocellular tumor tissues. The result suggests that the KIAA1099 gene may be linked to the pathogenesis of liver cancer.

誌謝....................................................I
表目錄..................................................II
圖目錄..................................................III
中文摘要................................................V
英文摘要................................................VI
縮寫表..................................................VII
壹﹑緒論................................................1
貳、實驗材料及方法......................................6
2.1實驗材料.........................................6
2.2實驗方法.........................................12
參﹑實驗結果............................................20
3.1生物資訊學的應用.................................20
3.2實驗數據.........................................25
3.3繪製人類ArfGAP基因家族之演化樹...................28
肆﹑討論................................................30
伍﹑未來展望............................................33
陸﹑參考文獻............................................34

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