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  • Deposited research article
  • Open Access

Short segmental duplication: parsimony in growth of microbial genomes

Genome Biology20034:P7

  • Received: 1 August 2003
  • Published:


We compare the distributions of occurrence frequencies of oligonucleotides two to ten bases long (2 to 10-mers) in microbial complete genomes with corresponding distributions obtained from random sequences and find that the genomic distributions are uniformly many times wider in a universal manner, that is, the same for all microbial complete genomes. The difference increases with decreasing word length, with the genomic spectral width about 40 times wider for 2-mers. We show that the observed genomic properties are characteristic of sequences generated in a simple growth model, where a very short initial random sequence (less than 1 kb) grows mainly by maximally stochastic duplication of short segments (of about 25 b). We discuss a number issues related to the findings and the model, including the proposition that life began in an RNA world before the birth of proteins.


  • Random Sequence
  • Segmental Duplication
  • Model Sequence
  • Microbial Genome
  • Neisseria Meningitidis