Circular DNAs are extra-chromosomal fragments that become circularized by 
genomic recombination events. We have recently shown that yeast LTR elements 
generate circular DNAs through recombination events between their flanking long 
terminal repeats (LTRs). Similarly, circular DNAs can be generated by 
recombination between LTRs residing at different genomic loci, in which case the 
circular DNA will contain the intervening sequence. In yeast, this can result in 
gene copy number variations when circles contain genes and origins of 
replication. Here, I speculate on the potential and implications of circular 
DNAs generated through recombination between human transposable elements.