Eukaryotic Intron Loss Tobias Mourier & Daniel C. Jeffares

Introns Pre-mRNA DNA mRNA

Intron evolution Bacteria -introns Archaea -introns Eukaryota +introns Introns early/Introns late

Intron evolution

ATGAAGCGATGT MetLysArgCys Intron fase 0 Intron fase 1 Intron fase 2 “Exon Theory of Genes”

Eukaryotic intron loss Fink GR, Cell 49, 5 (1987): Introns i Saccharomyces cerevisiae ligger oftest i 5’ (starten) af genet Introns er tabt gennem rekombination med revers transkriberet cDNA

Eukaryotic intron loss mRNA cDNA Revers transkription

Eukaryotic intron loss mRNA cDNA

Eukaryotic intron loss mRNA cDNA Probability of cDNA coverage 5’ Position 3’

Eukaryotic intron loss mRNA cDNA Probability of cDNA coverage 5’ Position 3’

Eukaryotic intron loss Mammals Homo sapiens Rattus norvegicus Mus musculus Vertebrates Takifugu rubripes Danio rerio Invertebrates Caenorhabditis elegans Anopheles gambiae Drosophila melanogaster Plants Arabidopsis thaliana Oryza sativa japonica Fungi Neurospora crassa Schizosaccharomyces pombe Saccharomyces cerevisiae Encephalitozoon cuniculi (Magnaporthe grisae) Alveolates Plasmodium falciparum Plasmodium yoelii yoelii Slime mold Dictyostelium discoideum (chr. II) Red algae Guillardia theta nucleomorph ~ gener ~ introns

Eukaryotic intron loss A B Relative Intron Position = A/B

Homo sapiens (8.4) Rattus norvegicus (8.3) Mus musculus (7.6) C. elegans (5.2) A. thaliana (4.2) Oryza sativa (3.2) Takifugu rubripes (3.1) Danio rerio (3.0) Anopheles gambiae (2.8) D. melanogaster (2.7) Magnaporthe grisea (1.9) Neurospora crassa (1.7) Plasmodium falciparum (1.3) Dictyostelium discoideum II (1.2) Plasmodium yoelii yoelii (1.1) Schizosaccharomyces pombe (0.95) Saccharomyces cerevisiae (0.045) Guillardia theta nucleomorph (0.035) Encephalitozoon cuniculi (0.0075) Relative intron position 5’  3’ Fraction of introns

Relative intron position 5’  3’ Fraction of introns Intron erhvervelse eller Intron tab

5’ Intron erhvervelse 3’ Intron tab Insertions bias? Positions-afhængig selektion?

Intron erhvervelseIntron tab

Intron erhvervelseIntron tab

Intron erhvervelseIntron tab

Eukaryotic intron loss Mammals Homo sapiens Rattus norvegicus Mus musculus Vertebrates Takifugu rubripes Danio rerio Invertebrates Caenorhabditis elegans Anopheles gambiae Drosophila melanogaster Plants Arabidopsis thaliana Oryza sativa japonica Fungi Neurospora crassa Schizosaccharomyces pombe Saccharomyces cerevisiae Encephalitozoon cuniculi (Magnaporthe grisae) Alveolates Plasmodium falciparum Plasmodium yoelii yoelii Slime mold Dictyostelium discoideum (chr. II) Red algae Guillardia theta nucleomorph Sidste fælles stamform?

Johnson PJ, Proc Natl Acad Sci USA 99, 3358 (2002) Dacks JB, Doolittle WF, Cell 107, 419 (2001) SSU rRNA

Stechmann A, Cavalier- Smith T, Science 297, 89 (2002) Gene fusion

Baldauf SL, Science 300, 1703 (2003) Konsensus (molekylære & strukturelle data)

Få introns i encellede eukaryoter er en afledt karakter Den sidste fælles stamform (sidste fælles eukaryot?) var intron-rig Eukaryotic intron loss