%0 Journal Article
%T Novel Genes from Formation to Function
%A Rita Ponce
%A Lene Martinsen
%A Lu¨ªs M. Vicente
%A Daniel L. Hartl
%J International Journal of Evolutionary Biology
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/821645
%X The study of the evolution of novel genes generally focuses on the formation of new coding sequences. However, equally important in the evolution of novel functional genes are the formation of regulatory regions that allow the expression of the genes and the effects of the new genes in the organism as well. Herein, we discuss the current knowledge on the evolution of novel functional genes, and we examine in more detail the youngest genes discovered. We examine the existing data on a very recent and rapidly evolving cluster of duplicated genes, the Sdic gene cluster. This cluster of genes is an excellent model for the evolution of novel genes, as it is very recent and may still be in the process of evolving. 1. Introduction The availability of complete genome sequences allows the comparison of genomes, thus revealing the differences in gene complement and demonstrating the nature of the changes that occur in the evolution of genomes. In particular, genomic analysis showed that more than one-third of the eukaryotic genome is composed of gene duplications and gene families (e.g., [1¨C4]), highlighting the prominence of duplications in the evolution of genomes. The study of whole genomes also allows an analysis of the rates and dynamics of duplications as well as the divergence and silencing of duplicates (e.g., [5¨C7]). Moreover, evidence indicates that the rates of duplication are extremely high and of the same order of magnitude as the rate of mutation per nucleotide; for example, the frequency of duplication for coding genes was found to be 0.01 per gene per million years [8] and for internal duplications of gene segments, 0.001¨C0.013 duplications/gene per million years [9]. The fates of gene duplicates can be very different according to the mutations they undergo and the selective pressures they are under. After a gene is duplicated, the most common fate seems to be the loss of function of one copy by the acquisition of degenerative mutations, while the other copy retains the original function. The originally identical copies can also both be maintained in the genome, allowing a higher production of the corresponding RNA or protein. Subsequent mutation by retrotransposon insertion into one of the copies can affect adaptive evolution because the effect on the phenotype can in some cases be beneficial to the organism [10]. Partial gene duplications can also occur, and if the duplicated part involves a structural or functional domain the new gene can increase the functional complexity of the encoded protein. It has also been proposed that if two copies of
%U http://www.hindawi.com/journals/ijeb/2012/821645/