Eukaryotic DNA replication is highly stratified, with different genomic regions 
shown to replicate at characteristic times during S phase. Here we observe that 
mutation rate, as reflected in recent evolutionary divergence and human 
nucleotide diversity, is markedly increased in later-replicating regions of the 
human genome. All classes of substitutions are affected, suggesting a 
generalized mechanism involving replication time-dependent DNA damage. This 
correlation between mutation rate and regionally stratified replication timing 
may have substantial evolutionary implications.