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Internet Electronic Journal of Molecular Design - IEJMD, ISSN 1538-6414, CODEN IEJMAT
| ABSTRACT - Internet Electron. J. Mol. Des. October 2002, Volume 1, Number 10, 545-558 |
Investigations on Evolutionary Changes in Base Distributions
in Gene Sequences
Ashesh Nandy
Internet Electron. J. Mol. Des. 2002, 1, 545-558
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Abstract:
We had observed that 2D graphical plots of DNA sequences show
apparently systematic variations among members of families of
gene sequences and reported these to be due to evolutionary
changes. Investigations of phylogenetic relationships between
species through studies of gene sequences has been one of the
prime areas of interest to molecular biologists. While questions
such as rate of mutational changes in DNA sequences have been
investigated extensively, attention is being given recently to
changes in base distribution within such sequences. Roman-Roldan
et al. has shown that complexity of base organization in intron
segments increases with evolution. We use the 2D graphical
representation method to map the DNA sequences and use four
numerical techniques to quantitatively measure the differences
observed in the different gene sequences. We report here our
investigations using a graphical technique for DNA sequence
representation and related analyses for conserved gene sequences
such as kinetoplasts, heat shock proteins, globins and others. We
find that there are strong indications that base composition and
distributions in protein coding regions progresses with evolution
towards an equi-proportional composition and more complex
mixing of the four nucleotides which we term as asymptotic
complexity. Thus it is possible that increase in base mixing
complexity is a general feature of the evolution of gene sequences.
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