SREL Reprint #2342

Nucleotide variation in the p53 tumor-suppressor gene of voles from Chernobyl, Ukraine

J. Andrew DeWoody

Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
Department of Genetics, University of Georgia, Athens, GA 30602-7223, USA

Abstract: The 1986 Chernobyl disaster contaminated vast regions of Ukraine and Belarus with a variety of radioactive isotopes and heavy metals. While over 90% of the radioactive isotopes have decayed into stable compounds, radiation levels in contaminated areas are still extraordinarily high. In fact, some rodents living near the reactor have internal 134,137Cs concentrations approaching 80000 Bq/g. Several recent genetic analyses of vertebrates have illustrated that mutation rates of organisms exposed to radiation from Chernobyl are higher than in control groups, but none have studied DNA sequences. Nucleotide sequences of rodent mitochondrial genes were originally reported to have been hypervariable, but those results were subsequently retracted. Herein, I report the results of a pilot study to determine the extent of nucleotide variation at the p53 gene in four species of rodents (voles) from Chernobyl and from control sites. I sequenced a 788 bp region (coding and non-coding) of p53 in 30 different mice comprising four different species of Microtus. Nucleotide variation at the population level was due to deletions and substitutions; both were limited to introns. There were no significant differences between the number of haplotypes in radioactive and control populations (p = 0.60). Rare or private alleles might have arisen due to unique mutational pressures at Chernobyl. Alternatively, natural selection might have favored one allele over others (i.e., a selective sweep). Neither scenario is strongly supported by these data. Thus, no apparent genetic effects of the Chernobyl disaster on the p53 gene of resident voles were revealed; more extensive surveys will be necessary to determine if mutation rates are indeed elevated in mice from Chernobyl. However, two salient points emerge; the first involves the utility of introns as markers for mutations in coding regions and the second considers the relative merits of cloning in mutation detection studies.

Keywords: Mutation; Radiation; Microtus; intron; Exon; Cloning; Rodents

SREL Reprint #2342

DeWoody, J.A. 1999. Nucleotide variation in the p53 tumor-suppressor gene of voles from Chernobyl, Ukraine. Mutation Research 439:25-36.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).