title: Evolution of new functions de novo and from preexisting genes.
abstract: How the enormous structural and functional diversity of new genes and proteins was generated (estimated to be 10(10)-10(12) different proteins in all organisms on earth [Choi I-G, Kim S-H. 2006. Evolution of protein structural classes and protein sequence families. Proc Natl Acad Sci 103: 14056-14061] is a central biological question that has a long and rich history. Extensive work during the last 80 years have shown that new genes that play important roles in lineage-specific phenotypes and adaptation can originate through a multitude of different mechanisms, including duplication, lateral gene transfer, gene fusion/fission, and de novo origination. In this review, we focus on two main processes as generators of new functions: evolution of new genes by duplication and divergence of pre-existing genes and de novo gene origination in which a whole protein-coding gene evolves from a noncoding sequence.
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, SE-75123 Uppsala, Sweden.
authors.forename: Dan I
authors.initials: DI
authors.lastname: Andersson
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, SE-75123 Uppsala, Sweden.
authors.forename: Jon
authors.initials: J
authors.lastname: Jerlström-Hultqvist
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, SE-75123 Uppsala, Sweden.
authors.forename: Joakim
authors.initials: J
authors.lastname: Näsvall
mesh_terms: D019143:Evolution, Molecular; D020440:Gene Duplication