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臺灣原住民MICA基因之遺傳人類學硏究
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| 作者 |
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楊茂年 |
| 學校系所 |
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慈濟大學人類學研究所 |
| 地點 |
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全臺 全部
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| 研究內容 |
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[ 摘要 ]
台灣原住民屬於南島民族，他們的起源、遷徙與演化一直是學者們研究的重要議題。遺傳學和考古學、語言學與民族學等學門都是研究原住民起源的重要工具，近年來在以基因標記探討台灣原住民親緣關係的研究中，血型、紅血球酵素系統、血清蛋白、HLA系統、Y染色體、粒線體DNA等標記皆已被研究，證據顯示島內原住民各族群間存在著相當的差異。
MICA是人類白血球抗原區域的一個基因，位置在HLA-B基因往著絲點大約46.4Kb的地方，全長總11719鹼基對，並有六個表現子，是一個相當多樣性的基因。MICA目前已知有58個不同的等位基因，它的高度基因多態性對於研究族群間的親緣關係有相當大的幫助。
分析阿美、泰雅、太魯閣、鄒等族共94個DNA樣本，總共發現了個等位基因，其中15個有族群間共享的情形。28個等位基因中有18個是新發現的序列，其中9個有共享的情形。除了MICA*N16由鄒與太魯閣共享外，剩下8個的共享發生在阿美、泰雅與太魯閣之間。
MICA*00801在這些族群中都有著高比例的存在，同時也存在於其他地區的族群中，很有可能是世系群II的演化中心，這次研究中有30%的新等位基因是由MICA*00801直接演化出來的。MICA*019在阿美、泰雅、太魯閣和鄒族都有發現，也有可能是台灣原住民族群的古老的等位基因。泰雅和太魯閣一向被認為兩個沒有明顯差異的族群，卻僅共享4個等位基因，顯示已經有分化的現象產生。阿美與泰雅雖然共享了9個等位基因，但是在遺傳距離的計算上卻仍然較疏遠，共享的情形可能是因為天擇或其他原因所造成的。
比較台灣原住民與其他族群的MICA資料，發現台灣原住民少了一個其他族群都擁有的等位基因－MICA*00201，他們與東北亞民族共享的等位基因也僅有MICA*00801與MICA*010兩個，在親緣關係樹上更可以明顯的看出台灣原住民與東北亞民族的關係是疏遠的。
[ 英文摘要 ]
Taiwan aborigines are Austronesian speakers. Their origins, migrations and evolution are important research topics for anthropologists. In recent years, scholars have used many genetic marks to study Taiwan aborigines including blood groups, red cell enzymes, serum proteins, HLA, SNP on Y chromosome and mitochondrial DNA. The results of these studies indicated that there are significant differences among Taiwan aboriginal populations.
MICA is a gene in HLA region, located 46 kb centromeric to HLA-B locus. It is 11,719 base pairs long and contains 6 exons. MICA is highly polymorphic; there are at least 58 known MICA alleles
Ninety-four DNA samples, including people from Amis, Atayal, Truku and Tsou tribes, were analyzed in this study. We found 28 MICA alleles in these samples: 15 alleles are shared by at least two tribes, and 18 alleles are novel.
MICA*00801 is of high frequency in four Taiwan aboriginal populations and other populations in the World. MICA alleles of Lineage II might originate from MICA*00801. In our research, 30% of novel alleles is directly originated from MICA*00801. MICA*019 were also found in Amis, Atayal, Truku and Tsou. It might be an ancient allele in Taiwan aborigines. It is though that Atayal and Truku shared close relationship. However, our results showed that they might have diverged from each other.
MICA*00201 were found in all other populations in the World but lost in Taiwan aborigines. Also, Taiwan aborigines and Northeast Asians only share two alleles: MICA*00801 and MICA*010. They do not share close relationship in the phylogeny tree. The distribution of MICA alleles in Taiwan aboriginal populations suggests that their genetic backgrounds are unique.
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