Human Lineage-Specific

Pseudogenes are nonfunctional vestiges of genes. Inves-tigating genes that were inactivated specifically on the human lineage or within humans can reveal the genetic basis of interspecies differences between humans and chimpanzees and interindividual differences within humans. It can also help understand the selective pres-sures that altered during human evolution or vary among humanpopulations.Recentgenome-widesurveys showed that human-specific pseudogenisation events occurred much more frequently to chemosensory and immune response genes than to other genes. Although non-deleterious pseudogenisation events were traditionally considered to be neutral, emerging evidence suggests that some of them are beneficial. One well-characterised case is the human CASP12 locus, where the null allele decreases the incidence of sepsis and has apparently been selected for in human evolution. Exploration of roles of pseudogenisation in genome evolution and phenotype evolution has started