Delhomme, Nicolas
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
Abstract
Plant mitogenomes can be difficult to assemble because they are structurally dynamic and prone to intergenomic DNA transfers, leading to the unusual situation where an organelle genome is far outnumbered by its nuclear counterparts. As a result, comparative mitogenome studies are in their infancy and some key aspects of genome evolution are still known mainly from pregenomic, qualitative methods. To help address these limitations, we combined machine learning and in silico enrichment of mitochondrial-like long reads to assemble the bacterial-sized mitogenome of Norway spruce (Pinaceae: Picea abies). We conducted comparative analyses of repeat abundance, intergenomic transfers, substitution and rearrangement rates, and estimated repeat-by-repeat homologous recombination rates. Prompted by our discovery of highly recombinogenic small repeats in P. abies, we assessed the genomic support for the prevailing hypothesis that intramolecular recombination is predominantly driven by repeat length, with larger repeats facilitating DNA exchange more readily. Overall, we found mixed support for this view: Recombination dynamics were heterogeneous across vascular plants and highly active small repeats (ca. 200 bp) were present in about one-third of studied mitogenomes. As in previous studies, we did not observe any robust relationships among commonly studied genome attributes, but we identify variation in recombination rates as a underinvestigated source of plant mitogenome diversity.
Keywords
mitogenome; repeats; recombination; rearrangement rates; structural variation
Published in
Genome Biology and Evolution
2020, volume: 12, number: 1, pages: 3586-3598
Publisher: OXFORD UNIV PRESS
SLU Authors
UKÄ Subject classification
Genetics and Genomics
Evolutionary Biology
Publication identifier
- DOI: https://doi.org/10.1093/gbe/evz263
Permanent link to this page (URI)
https://res.slu.se/id/publ/105334