生物谷報(bào)道：近日,，昆明動(dòng)物所馬普青年科學(xué)家小組的博士生楊爽等在導(dǎo)師王文研究員的指導(dǎo)下,，與芝加哥大學(xué)的科學(xué)家合作，經(jīng)過(guò)篩選和分析大量的果蠅年輕基因,，發(fā)現(xiàn)非等位的同源重組(non-allelic homologous recombination)遠(yuǎn)比傳統(tǒng)認(rèn)為的非同源重組重要得多,，從而取得了對(duì)基因重復(fù)機(jī)制的全新認(rèn)識(shí)。
本結(jié)果的論文于1月18日正式發(fā)表于國(guó)際著名遺傳學(xué)刊物PLoS Genetics上,。此前,，該小組已在新基因起源方面取得了一些研究成果，在Nature Genetics,、Plant Cell等學(xué)術(shù)刊物發(fā)表了一系列文章,，引起了國(guó)際同行的關(guān)注。
生物谷推薦英文原文：
PLoS Genetics
Received: August 22, 2007; Accepted: November 27, 2007; Published: January 18, 2008
Repetitive Element-Mediated Recombination as a Mechanism for New Gene Origination in Drosophila
Shuang Yang1,2, J. Roman Arguello3, Xin Li1,2, Yun Ding1,2, Qi Zhou1,2, Ying Chen4, Yue Zhang1, Ruoping Zhao1, Frédéric Brunet3¤, Lixin Peng1, Manyuan Long3,4*, Wen Wang1*
1 Chinese Academy of Sciences (CAS)—Max Planck Junior Research Group, Key Laboratory of Cellular and Molecular Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China, 2 Graduate School of Chinese Academy Sciences, Beijing, China, 3 Committee on Evolutionary Biology, The University of Chicago, Chicago, Illinois, United States of America, 4 Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, United States of America
Previous studies of repetitive elements (REs) have implicated a mechanistic role in generating new chimerical genes. Such examples are consistent with the classic model for exon shuffling, which relies on non-homologous recombination. However, recent data for chromosomal aberrations in model organisms suggest that ectopic homology-dependent recombination may also be important. Lack of a dataset comprising experimentally verified young duplicates has hampered an effective examination of these models as well as an investigation of sequence features that mediate the rearrangements. Here we use 7,000 cDNA probes (112,000 primary images) to screen eight species within the Drosophila melanogaster subgroup and identify 17 duplicates that were generated through ectopic recombination within the last 12 mys. Most of these are functional and have evolved divergent expression patterns and novel chimeric structures. Examination of their flanking sequences revealed an excess of repetitive sequences, with the majority belonging to the transposable element DNAREP1 family, associated with the new genes. Our dataset strongly suggests an important role for REs in the generation of chimeric genes within these species.
Figure 1.An Example Illustrating the Detection of New Genes
(A) The probe LD47348 (CG10595) detected two signals in the clade of D. yakuba-santomea-teissieri while only detecting one signal in other species. The new additional signal suggests a new gene candidate.
(B) Southern hybridization results further confirm the extra copy in the D. yakuba-santomea-teissieri clade (M is 1-kb extension marker [Invitrogen]). Lanes 1–8 correspond to Xho I digested DNAs of D. yakuba, D. teissieri, D. santomea, D. erecta, D. melanogaster, D. simulans, D. mauritiana, and D. sechellia, respectively).
(C) Cartoon figure displaying the gene structures of the parental gene (d, or CG10595) and the new duplicate (d-r). The duplicated region is indicated by vertical dash lines. d-r recruited one upstream exon as indicated by yellow box.
(D) Expression patterns of the parental gene. (E) expression patterns of the new gene d-r revealed by one round of RT-PCR and a second round of nested PCR (M indicates DL2000 DNA molecular marker (Takara); E+, E−, L2+, L2−, L3+, L3−, P+, P−, A+, and A− correspond to positive and negative reactions for embryos, second instar larvae, third instar larvae, pupae, and adults, respectively). From these gels, it is clear that d-r is only expressed in the third instar larvae while the parental copy is expressed ubiquitously. All the bands in the negative control lanes are primer dimer bands. E+ and L3+ are weak but clearly visible.
