Mating displays often contain multiple signals. Different combinations of these signals may be equally successful at attracting a mate, as environment and signal combination may influence relative signal weighting by choosy individuals. This variation in signal weighting among choosy individuals may facilitate the maintenance of polymorphic displays and signalling behaviour. One group of animals known for their polymorphic patterning are Batesian mimetic butterflies, where the interaction of sexual selection and predation pressures is hypothesized to influence the maintenance of polymorphic wing patterning and behaviour. Males in the female‐limited polymorphic Batesian mimetic butterfly Papilio polytes use female wing pattern and female activity levels when determining whom to court. They court stationary females with mimetic wing patterns more often than stationary females with non‐mimetic, male‐like wing patterns and active females more often than inactive females. It is unclear whether females modify their behaviour to increase (or decrease) their likelihood of receiving male courtship, or whether non‐mimetic females spend more time in cryptic environments than mimetic females, to compensate for their lack of mimicry‐driven predation protection (at the cost of decreased visibility to males). In addition, relative signal weighting of female wing pattern and activity to male mate selection is unknown. To address these questions, we conducted a series of observational studies of a polymorphic P. polytes population in a large butterfly enclosure. We found that males exclusively courted active females, irrespective of female wing pattern. However, males did court active non‐mimetic females significantly more often than expected given their relative abundance in the population. Females exhibited similar activity levels, and selected similar resting environments, irrespective of wing pattern. Our results suggest that male preference for non‐mimetic females may play an active role in the maintenance of the non‐mimetic female form in natural populations, where males are likely to be in the presence of active, as well as inactive, mimetic and non‐mimetic females.
Understanding the mechanisms by which mutations affect fitness and the distribution of mutational effects are central goals in evolutionary biology. Mutation accumulation (MA) lines have long been an important tool for understanding the effect of new mutations on fitness, phenotypic variation, and mutational parameters. However, there is a clear gap in predicting the effect of new mutations to their effects on fitness. Here we complete gene ontology analysis and metabolomics experiments on Arabidopsis thaliana MA lines to determine how spontaneous mutations affect global metabolic output in lines that have measured fitness consequences. For these analyses, we compared three lines with relative fitness consistently higher than the unmutated progenitor and three lines with lower relative fitness. In a gene ontology analysis, we find that the high fitness lines were significantly enriched in mutations in or near genes with transcription regulator activity. We also find that although they do not have an average difference in the number of mutations, low fitness lines have significantly more metabolic subpathways disrupted than high fitness lines. Taken together, these results suggest that the effect of a new mutation on fitness depends less on the specific metabolic pathways disrupted and more on the pleiotropic effects of those mutations and that organisms can explore a considerable amount of physiological space with only a few mutations.
The regulation of biochemical pathways is controlled at a variety of levels, from transcriptional timing to protein localization. Here we study the corticosteroid synthesis pathway in order to understand a transition from a biochemical pathway controlled by allosteric regulation to a phenotypically equivalent pathway controlled by differential expression of paralogs and enzyme specificity.The corticosteroids aldosterone and cortisol are produced in different layers of the adrenal cortex – a phenomenon known as zonation. Most mammals have a single enzyme, CYP11B, which produces aldosterone in the exterior layer of the adrenal cortex and cortisol in the interior layers. In mammals with a single‐CYP11B, the specific production of aldosterone and cortisol in different tissues is thought to be accomplished by allosteric regulation by another enzyme, CYP11A, which is only present in the interior layer of the cortex. It is thought that the presence of CYP11A changes the function of CYP11B so that it preferentially produces cortisol instead of aldosterone.However, throughout mammalian evolution CYP11B has duplicated independently in several lineages, giving rise to two CYP11B paralogs. These species still experience zonation and produce aldosterone and cortisol in different layers of the adrenal cortex. It has been demonstrated that this zonation in species with two CYP11B enzymes is accomplished by differential expression of the paralogs in the different tissues along with the evolution of enzymatic preference for their respective products. However, it is unknown whether the interaction between CYP11B and CYP11A has been lost and whether the zonation of hormones produced is regulated solely by the two differential expression and enzymatic activity of the CYP11B enzymes.Here we used Forster Resonance Energy Transfer (FRET) High Performance Liquid Chromatography (HPLC) to determine whether CYP11B and CYP11A physically interact and whether or not that interaction would contribute to the allosteric regulation of this pathway. Our preliminary analyses demonstrate a physical interaction between CYP11B and CYP11A in a single‐CYP11B species. Further experiments are aimed to test the interaction of duplicated CYP11Bs with CYP11A. We will monitor in vivo enzymatic assays by HPLC to determine what hormones are produced in the presence of different enzyme combinations. These results will shed light on the various ways metabolic pathways are regulated.Support or Funding InformationSD BRIN P20GM103443SD EPSCOR IIA‐1355423This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Understanding the mechanisms by which mutations affect fitness and the distribution of mutational effects are central goals in evolutionary biology. Mutation accumulation (MA) lines have long been an important tool for understanding the effect of new mutations on fitness, phenotypic variation, and mutational parameters. However, there is a clear gap in predicting the effect of specific new mutations to their effects on fitness. Here, we complete gene ontology analysis and metabolomics experiments on Arabidopsis thaliana MA lines to determine how spontaneous mutations directly affect global metabolic output in lines that have measured fitness consequences. For these analyses, we compared three lines with relative fitness consistently higher than the unmutated progenitor and three lines with lower relative fitness as measured in four different field trials. In a gene ontology analysis, we find that the high fitness lines were significantly enriched in mutations in or near genes with transcription regulator activity. We also find that although they do not have an average difference in the number of mutations, low fitness lines have significantly more metabolic subpathways disrupted than high fitness lines. Taken together, these results suggest that the effect of a new mutation on fitness depends less on the specific metabolic pathways disrupted and more on the pleiotropic effects of those mutations, and that organisms can explore a considerable amount of physiological space with only a few mutations.
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