title: Rapid birth-and-death evolution of imprinted snoRNAs in the Prader-Willi syndrome locus: implications for neural development in Euarchontoglires.
abstract: Imprinted small nucleolar RNAs (snoRNAs) are only found in eutherian genomes and closely related to brain functions. A complex human neurological disease, Prader-Willi syndrome (PWS), is primarily attributed to the deletion of imprinted snoRNAs in chromosome 15q11-q13. Here we investigated the snoRNA repertoires in the PWS locus of 12 mammalian genomes and their evolution processes. A total of 613 imprinted snoRNAs were identified in the PWS homologous loci and the gene number was highly variable across lineages, with a peak in Euarchontoglires. Lineage-specific gene gain and loss events account for most extant genes of the HBII-52 (SNORD115) and the HBII-85 (SNORD116) gene family, and remarkable high gene-birth rates were observed in the primates and the rodents. Meanwhile, rapid sequence substitution occurred only in imprinted snoRNA genes, rather than their flanking sequences or the protein-coding genes located in the same imprinted locus. Strong selective constraints on the functional elements of these imprinted snoRNAs further suggest that they are subjected to birth-and-death evolution. Our data suggest that the regulatory role of HBII-52 on 5-HT2CR pre-mRNA might originate in the Euarchontoglires through adaptive process. We propose that the rapid evolution of PWS-related imprinted snoRNAs has contributed to the neural development of Euarchontoglires.
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, and School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China.
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, and School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Yang
authors.affiliation: Laboratory of Liver Disease Hospital, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, P. R. China.
authors.forename: Qiao-Su
authors.initials: QS
authors.lastname: Shi
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, and School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China.
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Zheng
authors.affiliation: Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, P. R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, and School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, and School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China.
authors.forename: Liang-Hu
authors.initials: LH
authors.lastname: Qu
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D056426:Genetic Loci / Q000235:genetics*; D018392:Genomic Imprinting / Q000235:genetics*; D006801:Humans; D008322:Mammals / Q000235:genetics*; D055495:Neurogenesis / Q000235:genetics*; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D011218:Prader-Willi Syndrome / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020537:RNA, Small Nucleolar / Q000235:genetics*; D012641:Selection, Genetic
chemical_list: D012333:RNA, Messenger; D020537:RNA, Small Nucleolar