Within‐population genetic effects of mtDNA on metabolic rate in Drosophila subobscura

Abstract

A growing body of research supports the view that within-species sequence variation in the mitochondrial genome (mtDNA) is functional, in the sense that it has important phenotypic effects. However, most of this empirical foundation is based on comparisons across populations, and few studies have addressed the functional significance of mtDNA polymorphism within populations. Here, using mitonuclear introgression lines, we assess differences in whole-organism metabolic rate of adult Drosophila subobscura fruit flies carrying either of three different sympatric mtDNA haplotypes. We document sizeable, up to 20%, differences in metabolic rate across these mtDNA haplotypes. Further, these mtDNA effects are to some extent sex specific. We found no significant nuclear or mitonuclear genetic effects on metabolic rate, consistent with a low degree of linkage disequilibrium between mitochondrial and nuclear genes within populations. The fact that mtDNA haplotype variation within a natural population affects metabolic rate, which is a key physiological trait with important effects on life-history traits, adds weight to the emergent view that mtDNA haplotype variation is under natural selection and it revitalizes the question as to what processes act to maintain functional mtDNA polymorphism within populations.

Divergent evolution of life span associated with mitochondrial DNA evolution

“…; Kurbalija Novičić et al. ), including life span, growth rate, metabolic rate, behavior, viability, and even fitness. It therefore seems likely that the mitochondrion plays an important role not only for ageing, but more generally for multidimensional life‐history syndromes (Ballard and Pichaud ; Løvlie et al.…”

Negative frequency dependent selection on sympatric mtDNA haplotypes in Drosophila subobscura

“…In this species, variation is ubiquitous and strikingly geographically homogenous, with two dominant mtDNA haplotypes (termed I and II) typically co- occurring within populations at stable frequencies of approximately 50:50, across both the new and the old world [9, 22–28]. Moreover, experimental studies have shown that the two mtDNA haplotypes are not functionally equivalent: flies that harbor these haplotypes differ in major life history traits such as metabolic rate [29], fertility [30], viability, longevity and desiccation resistance [8, 31] and two earlier studies of laboratory cage populations were able to reject genetic drift as the sole mediator of mtDNA haplotype changes [9, 32]. These observations prompted a large experimental effort by Oliver et al [33], where replicated cage populations of D. subobscura were founded by flies carrying either of the two haplotypes (at 50:50) and haplotype frequencies were then monitored for 33 generations.…”

“…Another, perhaps more likely, possibility is that the nuclear genetic background differed between the two studies. The nuclear background is known to, through mitonuclear epistasis, affect the relative fitness of the two haplotypes [29, 31] as well as their evolutionary dynamics [9]. …”

Molecular tracing of the transmission routes of bois noir in Mediterranean vineyards of Montenegro and experimental evidence for the epidemiological role of Vitex agnus‐castus (Lamiaceae) and associated Hyalesthes obsoletus (Cixiidae)

“…First, there are documented data on substantial genetic divergence of Israeli populations of Vitex ‐associated H. obsoletus from European populations (Johannesen et al ., ; Imo et al ., ), which could also be reflected in the phenotypic and metabolic characteristics of the insects (e.g. Kurbalija Novičić et al ., ). In Israel, Vitex ‐associated H. obsoletus is characterized by two flight periods per year (April–July and September–November; Sharon et al ., ); but on the Adriatic and Aegean coasts of the Mediterranean, H. obsoletus on V. agnus‐castus has one prolonged flight period, starting at the end of June, with peak activity in mid‐July and declining until the end of September or the beginning of October (J. Jović and I. Toševski, unpublished data).…”