Alpha radiation is a major germ-line mutagen over evolutionary timescales

Question: Is alpha radiation responsible for major changes in genome structure, including karyotypic change and higher ploidy? In vitro, high doses of alpha radiation yield many chromosomal changes, while low doses yield mostly point mutations. Data description: Previously published data on karyotypic variability and the incidence of polyploidy in various animal and plant species. Search method: In nature, most alpha radiation exposure is caused by radon progeny. Exposure is particularly high below ground, and is also elevated on plant surfaces due to deposition by rain. I look for correlations between the degree of karyotypic variability (or polyploidy) and exposure to alpha radiation. Conclusions: Both karyotypic variability and the frequency of polyploidy are associated with ecological exposure to alpha radiation. The associations are consistent with observed differences in synonymous substitution rates between species. These results suggest that alpha radiation is the dominant evolutionary mutagen for some species.