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Identifying Amino Acid Overproducers Using Rare-Codon-Rich Markers

Identifying Amino Acid Overproducers Using Rare-Codon-Rich Markers

Published on: June 24, 2019

Avoidance of long mononucleotide repeats in codon pair usage.

Tingting Gu¹, Shengjun Tan, Xiaoxi Gou

¹State Key Laboratory of Pharmaceutical Biotechnology, Department of Biology, Nanjing University, Nanjing 210093, China.

|September 1, 2010

Summary

Mononucleotide repeats influence codon pair bias across all life, with organisms avoiding long repeats to maintain genetic stability and prevent frameshift mutations. This suggests a general evolutionary mechanism shaping genome composition.

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Area of Science:

Genomics
Molecular Biology
Evolutionary Biology

Background:

Codon usage bias is a known phenomenon in protein synthesis.
Mononucleotide repeats are highly mutable, but their impact on codon pair preference is understudied.

Purpose of the Study:

To investigate the relationship between mononucleotide repeats and codon pair bias.
To determine if this relationship is conserved across different life kingdoms.

Main Methods:

Genomic survey across bacteria, archaea, and eukaryotes.
Analysis of codon pair bias, distinguishing it from codon usage bias.
Examination of mononucleotide repeat patterns and their association with observed/expected ratios.

Main Results:

Strong avoidance of five or six consecutive identical nucleotides in codon pairs.
Lower observed/expected ratios for codon pairs with G or C repeats compared to A or T repeats.
Negative correlation between genomic GC content and codon pair ratios, especially for G/C pairs.
Avoidance of G/C codon pairs in highly conserved genes.

Conclusions:

Evidence supports natural selection against long mononucleotide repeats to prevent frameshift mutations.
Observed patterns indicate a general phenomenon across all kingdoms of life.
Long mononucleotide repeats significantly impact gene base composition, genetic stability, and function.