The mitochondrial genome of a hybrid plant

SANCHEZ PUERTA, MV; M K ZUBKO; PALMER, JD

Bahia Blanca

Congreso; VI Argentinian Conference on Bioinformatics and Computational Biology; 2015

Asociacion Argentina de Bioinformatica y Biologia Computacional

This study is directly relevant to the evolution of plant mitochondrial genomes, which engage in horizontal gene transfer surprisingly often, including even the incorporation of entire mitochondrial genomes from other plants. It establishes that somatic hybrid formation can lead to a remarkably chimeric mitochondrial genome, through at least 35 homologous recombination events between parental genomes. The analyses provide important mechanistic insights: they identify homologous recombination as the predominant mechanism responsible, through the double-strand break repair (DSBR) and/or break-induced replication (BIR) pathways, with no evidence for illegitimate recombination. Despite its greatly increased size, the cybrid (cytoplasmic hybrid) mitochondrial genome has lost one parental allele of fully 90% of mitochondrial genes, which suggests that retaining a single form of each may be advantageous. This raises important questions with respect to potential underlying factors, including nuclear-cytoplasmic co-evolution and incompatibility, genetic homeostasis, and issues related to global gene expression.