Genetic approaches in comparative and evolutionary physiology

Abstract

Whole animal physiological performance is highly polygenic and highly plastic, and the same is generally true for the many subordinate traits that underlie performance capacities. Quantitative genetics, therefore, provides an appropriate framework for the analysis of physiological phenotypes and can be used to infer the microevolutionary processes that have shaped patterns of trait variation within and among species. In cases where specific genes are known to contribute to variation in physiological traits, analyses of intraspecific polymorphism and interspecific divergence can reveal molecular mechanisms of functional evolution and can provide insights into the possible adaptive significance of observed sequence changes. In this review, we explain how the tools and theory of quantitative genetics, population genetics, and molecular evolution can inform our understanding of mechanism and process in physiological evolution. For example, lab-based studies of polygenic inheritance can be integrated with field-based studies of trait variation and survivorship to measure selection in the wild, thereby providing direct insights into the adaptive significance of physiological variation. Analyses of quantitative genetic variation in selection experiments can be used to probe interrelationships among traits and the genetic basis of physiological trade-offs and constraints. We review approaches for characterizing the genetic architecture of physiological traits, including linkage mapping and association mapping, and systems approaches for dissecting intermediary steps in the chain of causation between genotype and phenotype. We also discuss the promise and limitations of population genomic approaches for inferring adaptation at specific loci. We end by highlighting the role of organismal physiology in the functional synthesis of evolutionary biology.

Asymmetric energetic costs in reciprocal-cross hybrids between carnivorous mice (Onychomys)

“…Understanding the genetic architecture of bioenergetic traits is a central focus in evolutionary physiology (Hayes and Garland, 1995;Storz et al, 2015). The pattern of maternally matched BMR in reciprocal F 1 hybrids reported here is consistent with mitochondrial control of energy metabolism in grasshopper mice ( Fig.…”

Hemoglobin–oxygen affinity in high-altitude vertebrates: is there evidence for an adaptive trend?

“…The first relates to the effect of environmentally induced variation, which can obscure phylogenetic signal in trait values (Garland et al, 2005;Storz et al, 2015a). Measurements of an environmentally labile trait (like the O 2 affinity of whole blood, which is influenced by red cell metabolism and acid-base status) may prevent an accurate assessment of the extent to which phenotypic similarity between a given pair of species is attributable to shared phylogenetic heritage versus a shared, plastic response to similar environmental conditions (i.e.…”

Hormones and the Evolution of Complex Traits: Insights from Artificial Selection on Behavior

“…The evolutionary origins of the vertebrate endocrine system are diverse (e.g., see Barrington (1987); Thornton (2001); Dean and Thornton (2007); Bridgham et al (2009);Sower et al (2009); pages R203-R204 in Storz et al (2015); Baker (2015); Schwartz and Bronikowski (2017)), and the ways it may respond to selection are manifold. Moreover, components of the overall endocrine system may be involved in a wide array of biological functions, such as involvement of the insulin and insulin-like signaling network in cell division and growth, organismal metabolism, growth and development, reproduction, and lifespan (Schwartz and Bronikowski 2017).…”

“…Comparative studies, however, are necessarily correlational and historical in nature (Abbott et al 2003;Goymann et al 2004) and cannot reveal the detailed generation-to-generation changes that occur in response to selection. Quantitative-genetic analyses and studies of selection in the wild can reveal the patterns of genetic and phenotypic variation in endocrine components that form the basis for individual variation and covariation as well as the higher-level phenotypes on which natural and sexual selection act in sex-, populationand context-specific ways (Shire 1976;Storz et al 2015;Cox et al 2017;Dantzer et al 2017). Beyond this, various types of phenoytpic engineering, e.g., by manipulating circulating levels of particular hormones, can help to elucidate both functional relations and selective importance (e.g., Ketterson et al 1996;Ketterson et al 2009;Cox et al 2014;Dantzer et al 2017).…”

“…Beyond this, various types of phenoytpic engineering, e.g., by manipulating circulating levels of particular hormones, can help to elucidate both functional relations and selective importance (e.g., Ketterson et al 1996;Ketterson et al 2009;Cox et al 2014;Dantzer et al 2017). Finally, phenotypic evolution can be studied directly with selection experiments and experimental evolution Garland and Rose 2009;Kawecki et al 2012;Storz et al 2015). Most germane to this paper, several studies have targeted rodent behavior for selective breeding and reported changes in other aspects of behavior, life history, and lower-level effectors of these organismal traits, including endocrine function (Hyde 1981;Rhodes and Kawecki 2009;Swallow et al 2009).…”