Hotel Estoril Eden, Monte Estoril,
5-8 October 2005



NextText Box: Participants
Text Box: Programme

stimation of Mutation Rates of Tri-Nucleotide Repeats in Escherichia coli

Jill Sales1, Rabaab Zahra2 and David Leach2
1Biomathematics and Statistics Scotland, UK
2Institute of Cell Biology, University of Edinburgh, UK

Trinucleotide repeat instability (expansions and deletions) is associated with human hereditary diseases such as Huntington’s disease, Myotonic dystrophy and Spinocerebellar ataxia. To investigate the fundamental mechanisms involved in instability, CTG/CAG repeat instability was studied in wild type and mutant E.coli strains. Repeats were integrated in the chromosome and the length of repeats among the sibling colonies was measured by PCR. The relative levels of instability in different strains may be quantified by determining the proportion of sibling colonies with altered repeat length. Here a new method is presented that models mutations using a stochastic branching process. Under certain assumptions, estimates of the underlying mutation rate for a single strain or the ratio of mutation rates from two strains may be obtained directly from the PCR results.