Genetic Footprints of Natural Selection and Drift in Human Evolution

Authors : Mehmet Somel, Efe Sezgin

Pages : 193-220

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Publication Date : 2010-08-01

Article Type : Other

Abstract :Humans are genetically little diverged from their closest living relatives, chimpanzees. However, human anatomy, physiology and behavior show substantial divergence from those of chimpanzees and other primates. The evolutionary processes that generated this phenotypic divergence are still debated. Given the incomplete state of the hominid fossil record, genetic information is indispensible for studying human evolution. Recently, data from genome sequencing projects, gene expression profiling, and large-scale genotyping across multiple populations, has significantly improved our understanding of human origins, as well as the forces of selection, adaptation, and demographic forces that shaped human evolution. Recent multispecies comparative genomic studies indicate that random genetic drift, i.e. neutral evolution, is a leading evolutionary mechanism in shaping human protein coding sequences, as well as gene expression patterns. Still, there is also compelling evidence that a large number of human genes were affected by adaptive evolution. Genes involved in immunity, sensory perception, reproduction, and apoptosis appear among the most frequently positively selected classes. Likewise, comparative transcriptome studies indicate adaptive expression changes in human brain gene expression
Keywords : Human evolution, Comparative genomics, Natural selection, Drift, Gene expression evolution