“…Although the chloroplast and mitochondria are the most frequently studied cytoplasmic factors, plasmids, prions, and viruses can also have heritable phenotypic effects [40, 41]. Work on a number of species has shown that cytonuclear interactions are pervasive [39] and can significantly influence complex traits, such as longevity in flies [42], flowering time, growth, and defense against herbivores and pathogens in plants [43, 44], and the growth effects of gene deletions in yeast [40]. A recent study on heritable variation in metabolism in an Arabidopsis cross is particularly relevant to the discussion of HGIs [45].…”