Intron gain and loss in the evolution of the conserved eukaryotic recombination machinery.
Intron conservation, intron gain or loss and putative intron sliding events were determined for a set of three genes (SPO11, MRE11 and DMC1) involved in basic aspects of recombination in eukaryotes. These are ancient genes and present in nearly all of the major kingdoms. MRE11 is of bacterial origin and can be found in all kingdoms. DMC1 is a specialized homolog of the bacterial RecA protein, whereas the SPO11 gene is of archaebacterial origin. Only unique homologs of SPO11 are found in animals and fungi whereas three distantly related SPO11 copies are present in plant genomes. A comparison of the respective intron positions and phases of all genes was performed, demonstrating that a quarter of the intron positions were perfectly conserved over more than 1 000 000 000 years. Regarding the remaining three quarters of the introns we found insertions to be about three times more frequent than deletions. Aligning the introns of the three different SPO11 homologs of Arabidopsis thaliana we propose a conclusive model of their evolution. We postulate that at least one duplication event occurred shortly after the divergence of plants from animals and fungi and that a respective homolog has been retained in a protist group, the apicomplexa.
Hartung
Frank
F
Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany.
Blattner
Frank R
FR
Puchta
Holger
H
D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D017124:Conserved Sequence; D003302:Coprinus / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D004706:Endodeoxyribonucleases / Q000235:genetics; D004950:Esterases / Q000235:genetics; D005057:Eukaryotic Cells; D019143:Evolution, Molecular; D005090:Exodeoxyribonucleases / Q000235:genetics; D006801:Humans; D007438:Introns; D008957:Models, Genetic; D016254:Mutagenesis, Insertional; D010802:Phylogeny; D051135:Rad51 Recombinase; D011938:Rec A Recombinases; D011995:Recombination, Genetic; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D000099257:Meiotic Recombination Protein SPO11
D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D004950:Esterases; D005090:Exodeoxyribonucleases; D051135:Rad51 Recombinase; D011938:Rec A Recombinases; D029701:Saccharomyces cerevisiae Proteins; D000099257:Meiotic Recombination Protein SPO11; C513033:DMC1 protein, S cerevisiae; C513034:ATDMC1 protein, Arabidopsis; C495146:ATRAD51 protein, Arabidopsis; C495153:RAD51 protein, human; C094191:MRE11 protein, S cerevisiae; C074556:DMC1 protein, human