The intron landscape of the mtDNA <i>cytb</i> gene among the Ascomycota: introns and intron-encoded open reading frames Tuhin K. Guha Alvan Wai Sahra-Taylor Mullineux Georg Hausner 10.6084/m9.figshare.5619637 https://tandf.figshare.com/articles/dataset/The_intron_landscape_of_the_mtDNA_i_cytb_i_gene_among_the_Ascomycota_introns_and_intron-encoded_open_reading_frames/5619637 <p>Fungal mitochondrial genes are frequently noted for the presence of introns. These introns are self-splicing and can be assigned to either group I or II introns and they can encode open reading frames (ORFs). This study examines the introns present within the cytochrome b (<i>cytb</i>) gene of ascomycetes fungi. Cytochrome b gene sequences were sampled from GenBank and supplemented with our own data for species of <i>Leptographium</i> and <i>Ophiostoma</i>. Group I introns were encountered most frequently, many encoding either LAGLIDADG or GIY-YIG homing endonucleases (HEs). Numerous examples of different intron/ORF arrangements were observed including nested ORFs, multiple ORFs within a single intron and intron ORFs at various stages of erosion due to the accumulation of mutations. In addition, we noted one example of a nested intron and one complex group II intron that could potentially allow for alternative splicing. Documenting the distribution of introns within the same gene across a range of species allows for a better understanding of the evolution of introns and intronic ORFs. Intron landscapes also are a resource that can help in annotating genes and in bioprospecting for potentially active HEs, which are rare-cutting DNA endonucleases with applications in biotechnology.</p> 2017-11-21 03:17:45 Group I and II introns nested introns homing endonucleases evolution