The Footprint of Evolution Duplication - Universal Equivalent Length of Genomes

• Main Authors: Hong Da, 陳鴻大
• Other Authors: H.C. Paul Lee
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/04516040165591592854

博士 === 國立中央大學 === 物理研究所 === 97 === 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.