Biology – Quantitative Biology – Populations and Evolution
Scientific paper
2004-10-19
Genetics 170 (2005) 831-840
Biology
Quantitative Biology
Populations and Evolution
Latex file, 11 pages including 5 ps figures; revised version; to appear in 'Genetics'
Scientific paper
Many modified genetic codes are found in specific genomes in which one or more codons have been reassigned to a different amino acid from that in the canonical code. We present a model that unifies four possible mechanisms for reassignment, based on the observation that reassignment involves a gain and a loss. The loss could be the deletion or loss of function of a tRNA or release factor. The gain could be the gain of a new type of tRNA for the reassigned codon, or the gain of function of an existing tRNA due to a mutation or a base modification. In the codon disappearance mechanism, the codon disappears from the genome during the period of reassignment. In the other mechanisms, the codon does not disappear. In the ambiguous intermediate mechanism, the gain precedes the loss; in the unassigned codon mechanism, the loss precedes the gain; and in the compensatory change mechanism, the loss and gain spread through the population simultaneously. We present simulations of the gain-loss model and demonstrate that all four mechanisms are possible. The frequencies of the different mechanisms are influenced by selection strengths, number of codons undergoing reassignment, directional mutation pressure and the possibility of selection for reduced genome size.
Higgs Paul G.
Sengupta Supratim
No associations
LandOfFree
A Unified Model of Codon Reassignment in Alternative Genetic Codes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Unified Model of Codon Reassignment in Alternative Genetic Codes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Unified Model of Codon Reassignment in Alternative Genetic Codes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-537641