Environmental effects on the genetic architecture of fitness components in a simultaneous hermaphrodite

Mutations shape genetic architecture and thus influence the evolvability, adaptation and diversification of populations. Mutations may have different and even opposite effects on separate fitness components, and their rate of origin, distribution of effects and variance-covariance structure may depend on environmental quality. We performed an approximately 1,500-generation mutation-accumulation (MA) study in diploids of the yeast Saccharomyces cerevisiae in stressful (high-salt) and normal environments (50 lines each) to investigate the rate of input of mutational variation (Vm) as well as the mutation rate and distribution of effects on diploid and haploid fitness components, assayed in the normal environment. All four fitness components in both MA treatments exhibited statistically significant mutational variance and mutational heritability. Compared to normal-MA, salt stress increased the mutational variance in growth rate by more than sevenfold in haploids derived from the MA lines. This increase was not detected in diploid growth rate, suggesting masking of mutations in the heterozygous state. The genetic architecture arising from mutation (M-matrix) differed between normal and salt conditions. Salt stress also increased environmental variance in three fitness components, consistent with a reduction in canalization. Maximum-likelihood analysis indicated that stress increased the genomic mutation rate by approximately twofold for maximal growth rate and sporulation rate in diploids and for viability in haploids, and by tenfold for maximal growth rate in haploids, but large confidence intervals precluded distinguishing these values between MA environments. We discuss correlations between fitness components in diploids and haploids and compare the correlations between the two MA environmental treatments.

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Genetic and maternal effects on juvenile survival and fitness-related traits in three populations of Atlantic salmon

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2014-0472 ◽

2015 ◽

Vol 72 (5) ◽

pp. 751-758 ◽

Cited By ~ 14

Author(s):

Aimee Lee S. Houde ◽

Craig A. Black ◽

Chris C. Wilson ◽

Trevor E. Pitcher ◽

Bryan D. Neff

Keyword(s):

Atlantic Salmon ◽

Maternal Effects ◽

Environmental Effects ◽

Genetic Architecture ◽

Life Stage ◽

Random Mating ◽

Genetic Effects ◽

Phenotypic Variance ◽

Offspring Performance ◽

Additive Genetic Effects

Although studies addressing natural selection have primarily focused on additive genetic effects because of their direct relationship with responses to selection, nonadditive genetic and maternal effects can also significantly influence phenotypes. We partitioned the phenotypic variance of survival and fitness-related traits in juvenile Atlantic salmon (Salmo salar) from three allopatric populations (LaHave, Sebago, and Saint-Jean) into additive genetic, nonadditive genetic, and maternal environmental effects using a full-factorial breeding design. We also modelled the potential increase in offspring performance if nonrandom mating (e.g., mate choice) is considered instead of random mating. The three populations exhibited significant differences in trait values as well as the genetic architecture of the traits. Nevertheless, nonadditive genetic and maternal environmental effects tended to be larger than the additive genetic effects. There was also a shift from maternal environmental to genetic effects during development in two of the populations. That is, maternal environmental effects were larger at early (egg and alevin) life stages, whereas nonadditive effects were larger at the later (fry) life stage. The amount of additive genetic effects was small, suggesting the traits will respond slowly to selection. We discuss how different maternal environmental effects across years may influence the genetic architecture of offspring traits.

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Genetic covariance between psychopathic traits and anticipatory skin conductance responses to threat: Evidence for a potential endophenotype

Development and Psychopathology ◽

10.1017/s0954579414001424 ◽

2015 ◽

Vol 27 (4pt1) ◽

pp. 1313-1322 ◽

Cited By ~ 4

Author(s):

Pan Wang ◽

Yu Gao ◽

Joshua Isen ◽

Catherine Tuvblad ◽

Adrian Raine ◽

...

Keyword(s):

Skin Conductance ◽

Environmental Effects ◽

Genetic Architecture ◽

Psychopathic Traits ◽

Psychopathic Personality ◽

Genetic Influences ◽

Genetic Covariance ◽

Aversive Stimuli ◽

Skin Conductance Responses ◽

Antisocial Tendencies

AbstractThe genetic architecture of the association between psychopathic traits and reduced skin conductance responses (SCRs) is poorly understood. By using 752 twins aged 9–10 years, this study investigated the heritability of two SCR measures (anticipatory SCRs to impending aversive stimuli and unconditioned SCRs to the aversive stimuli themselves) in a countdown task. The study also investigated the genetic and environmental sources of the covariance between these SCR measures and two psychopathic personality traits: impulsive/disinhibited (reflecting impulsive–antisocial tendencies) and manipulative/deceitful (reflecting the affective–interpersonal features). For anticipatory SCRs, 27%, 14%, and 59% of the variation was due to genetic, shared environmental, and nonshared environmental effects, respectively, while the percentages for unconditioned SCRs were 44%, 2%, and 54%. The manipulative/deceitful (not impulsive/disinhibited) traits were negatively associated with both anticipatory SCRs (r = –.14, p < .05) and unconditioned SCRs (r = –.17, p < .05) in males only, with the former association significantly accounted for by genetic influences (rg = –.72). Reduced anticipatory SCRs represent a candidate endophenotype for the affective–interpersonal facets of psychopathic traits in males.

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Imaging molecules adsorbed onto electrodes under potential control by scanning probe microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100086180 ◽

1991 ◽

Vol 49 ◽

pp. 376-377 ◽

Cited By ~ 1

Author(s):

N.J. Tao ◽

J.A. DeRose ◽

P.I. Oden ◽

S.M. Lindsay

Keyword(s):

Surface Charge ◽

Environmental Effects ◽

Scanning Probe Microscopy ◽

Statistical Significance ◽

Electrochemical Methods ◽

Surface Structures ◽

Scanning Probe ◽

Potential Control ◽

Afm Imaging ◽

Special Circumstances

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.

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