Evolutionary direction of processed pseudogenes

While some pseudogenes have been reported to play important roles in gene regulation, little is known about the possible rela- tionship between pseudogene functions and evolutionary process of pseudogenes, or about the forces responsible for the pseudogene evolution. In this study, we characterized human processed pseudogenes in terms of evolutionary dynamics. Our results show that pseudogenes tend to evolve toward： lower GC content, strong dinucleotide bias, reduced abundance of tran- scription factor binding motifs and short palindromes, and decreased ability to form nucleosomes. We explored possible evolu- tionary forces that shaped the evolution pattern of pseudogenes, and concluded that mutations in pseudogenes are likely deter- mined, at least partially, by neighbor-dependent mutational bias and recombination-associated selection.