Conservation Mitonuclear Replacement: Facilitated mitochondrial adaptation for a changing world.

Most species will not be able to migrate fast enough to cope with climate change, nor evolve quickly enough with current levels of genetic variation. Exacerbating the problem are anthropogenic influences on adaptive potential, including the prevention of gene flow through habitat fragmentation and the erosion of genetic diversity in small, bottlenecked populations. Facilitated adaptation, or assisted evolution, offers a way to augment adaptive genetic variation via artificial selection, induced hybridization, or genetic engineering.

Stronger evidence for relaxed selection than adaptive evolution in high-elevation animal mtDNA.

Mitochondrial (mt) genes are the subject of many adaptive hypotheses due to the key role of mitochondria in energy production and metabolism. One widespread adaptive hypothesis is that selection imposed by life at high elevation leads to the rapid fixation of beneficial alleles in mtDNA, reflected in the increased rates of mtDNA evolution documented in many high-elevation species. However, the assumption that fast mtDNA evolution is caused by positive, rather than relaxed purifying selection has rarely been tested.

A lethal mitonuclear incompatibility in complex I of natural hybrids.

The evolution of reproductive barriers is the first step in the formation of new species and can help us understand the diversification of life on Earth. These reproductive barriers often take the form of hybrid incompatibilities, in which alleles derived from two different species no longer interact properly in hybrids. Theory predicts that hybrid incompatibilities may be more likely to arise at rapidly evolving genes and that incompatibilities involving multiple genes should be common, but there has been sparse empirical data to evaluate these predictions.

Disentangling Positive Selection from Relaxed Selection in Animal Mitochondrial Genomes.

AbstractDisentangling different types of selection is a common goal in molecular evolution. Elevated / ratios (the ratio of nonsynonymous to synonymous substitution rates) in focal lineages are often interpreted as signs of positive selection. Paradoxically, relaxed purifying selection can also result in elevated / ratios, but tests to distinguish these two causes are seldomly implemented.

Oxytocin receptor antagonism during early vocal learning reduces song preference and imitation in zebra finches.

In species with vocal learning, acquiring species-typical vocalizations relies on early social orienting. In songbirds, for example, learning song requires dynamic social interactions with a "tutor" during an early sensitive period. Here, we hypothesized that the attentional and motivational processes that support song learning recruit the oxytocin system, which is well-understood to play a role in social orienting in other species.

Lead exposure is correlated with reduced nesting success of an urban songbird.

Lead exposure is a concern in urban ecosystems, with physiological and behavioral effects well documented in humans. Wildlife inhabiting urban ecosystems are also exposed to lead, yet little work has documented the sublethal effects of lead exposure in urban wildlife. We studied northern mockingbirds (Mimus polyglottos) in three neighborhoods of New Orleans, Louisiana, two with high soil lead and one with low soil lead, to better understand how lead exposure may influence mockingbirds' reproductive biology.

High mitochondrial mutation rates in are associated with nuclear-mediated changes in mitochondrial physiology.

Mitochondrial (mt) respiration depends on proteins encoded both by the mitochondrial and nuclear genomes. Variation in mt-DNA mutation rates exists across eukaryotes, although the functional consequences of elevated mt mutation rates in some lineages remain underexplored. In the angiosperm genus , closely related, ecologically similar species have either 'fast' or 'slow' mt-DNA mutation rates.

Thermal Responses Differ across Levels of Biological Organization.

Temperature is one of the most important environmental factors driving the genome-to-phenome relationship. Metabolic rates and related biological processes are predicted to increase with temperature due to the biophysical laws of chemical reactions. However, selection can also act on these processes across scales of biological organization, from individual enzymes to whole organisms.