scholarly journals Likely Scenarios of Intron Evolution

Author(s):  
Miklós Csűrös
Keyword(s):  
Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 1843-1851 ◽  
Author(s):  
John Parsch

AbstractIntron sizes show an asymmetrical distribution in a number of organisms, with a large number of “short” introns clustered around a minimal intron length and a much broader distribution of longer introns. In Drosophila melanogaster, the short intron class is centered around 61 bp. The narrow length distribution suggests that natural selection may play a role in maintaining intron size. A comparison of 15 orthologous introns among species of the D. melanogaster subgroup indicates that, in general, short introns are not under greater DNA sequence or length constraints than long introns. There is a bias toward deletions in all introns (deletion/insertion ratio is 1.66), and the vast majority of indels are of short length (<10 bp). Indels occurring on the internal branches of the phylogenetic tree are significantly longer than those occurring on the terminal branches. These results are consistent with a compensatory model of intron length evolution in which slightly deleterious short deletions are frequently fixed within species by genetic drift, and relatively rare larger insertions that restore intron length are fixed by positive selection. A comparison of paralogous introns shared among duplicated genes suggests that length constraints differ between introns within the same gene. The janusA, janusB, and ocnus genes share two short introns derived from a common ancestor. The first of these introns shows significantly fewer indels than the second intron, although the two introns show a comparable number of substitutions. This indicates that intron-specific selective constraints have been maintained following gene duplication, which preceded the divergence of the D. melanogaster species subgroup.


2014 ◽  
Vol 25 (1) ◽  
pp. 100-110 ◽  
Author(s):  
Yu Sun ◽  
Carrie A. Whittle ◽  
Pádraic Corcoran ◽  
Hanna Johannesson

2016 ◽  
Vol 8 (6) ◽  
pp. 1762-1775 ◽  
Author(s):  
Marjorie A. Hoy ◽  
Robert M. Waterhouse ◽  
Ke Wu ◽  
Alden S. Estep ◽  
Panagiotis Ioannidis ◽  
...  

1989 ◽  
Vol 35 (1) ◽  
pp. 210-214 ◽  
Author(s):  
Jørgen Kjems ◽  
Jonna Jensen ◽  
Tina Olesen ◽  
Roger A. Garrett

The structure of the exon–intron boundary was compared for an intron within 23S ribosomal RNA of Desulfurococcus mobilis and a newly discovered intron in tRNAMet from the same organism. The occurrence of a putative common structural feature suggests that intron excision occurs by the same mechanism. The possible recognition of this structural feature by the cleavage enzyme was investigated for the ribosomal RNA intron using RNA substrates exhibiting various exon and intron deletions. The results support the involvement of the structural features in the cleavage process. The evolutionary implications of these results are considered.Key words: archaebacteria, tRNA, ribosomal RNA, introns, intron evolution.


PLoS Genetics ◽  
2006 ◽  
Vol 2 (3) ◽  
pp. e25 ◽  
Author(s):  
Maki Yoshihama ◽  
Akihiro Nakao ◽  
Hung D Nguyen ◽  
Naoya Kenmochi

2006 ◽  
Vol 29 (1) ◽  
pp. 188-188
Author(s):  
J Flakowski ◽  
J Fahrni ◽  
I Bolivar ◽  
J Pawlowski
Keyword(s):  

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