| DC 欄位 |
值 |
語言 |
| DC.contributor | 物理學系 | zh_TW |
| DC.creator | 陳鴻大 | zh_TW |
| DC.creator | Hong Da | en_US |
| dc.date.accessioned | 2009-7-31T07:39:07Z | |
| dc.date.available | 2009-7-31T07:39:07Z | |
| dc.date.issued | 2009 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:444/thesis/view_etd.asp?URN=92242001 | |
| dc.contributor.department | 物理學系 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | 複製事件廣泛存在基因體的歷史當中，主導了基因序列的成長與演化。為了比較不同基因體間複製演化的共同特性，我們定義了序列的等價長度 l_e，等度價長度的直接意義即是，這個序列與長度 l_e 的隨機序列具有＂等價的隨機性質＂。也就是說，隨機序列的等價長度即等於自身的序列長，等價長度會在序列遭受隨機突變時增長，而在序列被複製時保持不變。
根據我們的研究，基因體具有普世的等價長度，且在染色體不同部分的等價長度皆相同，顯示原始的基因序列可能開始於一短序列，經由隨機片段複製作為演化動力而成長。這個結論與 RNA 世界假說相符合，而且能夠解釋存在先今基因體當中頻密的複製事件，或許也可為演化速率不平均的爭議提供解答。
| zh_TW |
| dc.description.abstract | Segmental duplication is widely held to be a dominant feature in the dynamics of
genome growth and evolution. Yet how this would a ect the global structure of
genomes has not been discused. Here, we identify the equivalent length, Le, of a
genomic sequence as a medium through which that dominance may be discussed
quantitatively. Through examining 865 complete chromosomes we nd the Le for a
genomic sequence to be nearly invariant and remarkably short compared true sequence
length { in terms of the statistics of two-letter words it is about 300 bases long { and
is approximately universal for all (examined) complete chromosomes. We verify this
result to be non-trivial, in particular, not caused by the similarity of sequences in
any commonly held sense, and demonstrate that it is easy to generate genome-like
sequences not having universal Le’’s. We establish a causal relation between short
Le and segmental duplication and show that a simple, random-segmental-duplication
driven model for genome growth generates highly diverse genome-like sequences that
have universal Le’’s. We postulate a connection between the universal value of Le and
maximum information capacity in genomic sequences and infer that the universality of
Le is a crucial product of the evolution of genome toward maximum tness.
| en_US |
| DC.subject | 演化 | zh_TW |
| DC.subject | RNA世界 | zh_TW |
| DC.subject | 複製 | zh_TW |
| DC.subject | 等價長度 | zh_TW |
| DC.subject | Evolution | en_US |
| DC.subject | Duplication | en_US |
| DC.subject | Equivalent Length | en_US |
| DC.subject | RNA word | en_US |
| DC.title | 演化複製的足跡 - 基因體的普適等價長度 | zh_TW |
| dc.language.iso | zh-TW | zh-TW |
| DC.title | The Footprint of Evolution Duplication - Universal Equivalent Length of Genomes | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |