High levels of fluctuating asymmetry in populations of Apodemus flavicollis from the most contaminated areas in Chornobyl.
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. FA of skulls of A. flavicollis may indicate the degree to which the level of radioactive contamination affects the development of animals at Chornobyl. However, the mechanisms leading to these effects are not clear and probably vary from population to population. There were significant correlations between the overall right to left differences for the Procrustes aligned shape configurations, centroid sizes, and intramuscular (137)Cs. Detectable effects of radiation on developmental stability probably start to occur between 0.132 and 0.297 microGy/h.
Savannah River Ecology Laboratory of the University of Georgia, Drawer E, Aiken, SC 29802, USA. oleksyk@ncifcrf.gov
Taras K
TK
Oleksyk
James M
JM
Novak
James R
JR
Purdue
Sergiy P
SP
Gashchak
Michael H
MH
Smith
D000818:Animals; D001699:Biometry; D002588:Cesium Radioisotopes / Q000032:analysis; D004784:Environmental Monitoring; D005260:Female; D005828:Genetics, Population; D008297:Male; D009115:Muridae / Q000033:anatomy & histology* / Q000235:genetics*; D010641:Phenotype; D011210:Power Plants; D011847:Radioactive Fallout / Q000032:analysis*; D018788:Radioactive Hazard Release; D012886:Skull / Q000033:anatomy & histology*; D014018:Tissue Distribution; D014455:Ukraine
D002588:Cesium Radioisotopes; D011847:Radioactive Fallout