Hereditary symbionts and mitochondria: distribution in insect populations and quasi-linkage of genetic markers

Abstract

Maternal transmission ensures the joint transmission and simultaneous presence in populations of individuals with certain variants of the bacterial symbiont and host mitochondrial DNA. Such “quasi-linkage” of cytoplasmic genomes among insects and other arthropods is widespread. The symbiont acts as a “driver” of mitochondria and the obvious biological consequence is the spread of the “linked” mitochondrial haplotype in the population, which itself does not have increased selective value to the organism. Examples of such indirect selective mitochondrial sweep in insects are discussed, as well as biological consequences of this phenomenon and mechanisms of increasing the frequency of symbiont-infected individuals in the population.