The Scientist (Internet / Print) 05/03/06 Spontaneous oxidative DNA damage may drive much of human genomic diversity by inducing single nucleotide polymorphisms (SNPs) and meiotic recombination, according to a new study in Genome Research. These findings reveal a mechanism by which environmental insults and oxidative metabolism may cause genetic mutations. The authors found that an oxidized form of the DNA base guanine called 8-oxoguanine (8-oxoG) was distributed unevenly across the genome, and regions dense in 8-oxoG showed abnormally high levels of recombination and SNPs. A causal connection between 8-oxoG and recombination or SNPs, however, is "still in the realm of speculation," said Sankar Mitra of the University of Texas Medical Branch. "This is a correlative conclusion. There's no direct proof." Also, 8-oxoG is just one type of DNA damage resulting from oxidative stress, Mitra said, and others have been linked to recombination as well.