SREL Reprint #2730




High levels of fluctuating asymmetry in populations of Apodemus flavicollis from the most contaminated areas in Chornobyl

Taras K. Oleksyk1,2,3, James M. Novak1,2, James R. Purdue4, Sergiy P. Gashchak5,
and Michael H. Smith1,2

1The University of Georgia's, Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA
2Institute of Ecology, The University of Georgia, Athens, GA 30602, USA
3Laboratory of Genomic Diversity, National Cancer Institute, NIH, Frederick, MD, USA
4Illinois State Museum, 1011 East Ash St., Springfield, IL 62703, USA
5International Radioecology Laboratory, Slavutych 07100, Ukraine

Abstract: Random deviations from the perfect symmetry of normally bilaterally symmetrical characters for an individual with a given genotype occur during individual development due to the influence of multiple environmental factors. Fluctuating asymmetry (FA) is often used as a measure of developmental instability, and can be estimated as the variance of the distribution of differences between the left and right sides. We addressed the question of whether levels of FA were elevated in radioactively contaminated populations living around Chornobyl compared to those in reference populations of the yellow-necked mouse (Apodemus flavicollis). In addition, we studied amounts of directional asymmetry (DA) when one side is larger than the other on average. There was a significant difference among populations, including reference populations, in the amount of both FA and DA. A higher level of FA was documented for the contaminated populations in close proximity to the failed Chornobyl reactor for both the asymmetry of size and shape. The FAs of size and shape were highest in populations from the most contaminated locations in the Chornobyl exclusion zone. Although the directional asymmetry of shape was also highest in the contaminated populations, it was not significantly different from those in most of the reference populations. Populations from less contaminated areas inside the Chornobyl exclusion zone did not express FA values different from those of the reference populations outside the affected area.

SREL Reprint #2730

Oleksyk, T. K., J. M. Novak, J. R. Purdue, S. P. Gashchak, and M. H. Smith. 2004. High levels of fluctuating asymmetry in populations of Apodemus flavicollis from the most contaminated areas in Chornobyl. Journal of Environmental Radioactivity 73:1-20.

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