Evolutionary Biology

eLife Assessment

This study leverages an impressive and comprehensive longitudinal 16S rRNA gut microbiome dataset from baboons to provide important insight regarding the use of a microbiome-based clock to predict biological age. The evidence for age-associated microbiome features and environmental and social variables that impact microbiome aging is convincing. This study of microbiomes as markers of host age will fuel inquiries and studies and interest a broad range of researchers, especially those interested in alternatives to measuring biological aging.

eLife Assessment

This study makes the important finding that pleiotropy is positively associated with parallelism of evolutionary responses in gene expression. This finding, if true, runs counter to current expectations in the field. The analysis uses state-of-the art experimental evolution approach to study the genetic basis of adaptation of Drosophila simulans to a hot environment. Although the experimental results are convincing, the theoretical model is incomplete, due to several unusual assumptions. It remains to be seen whether the main conclusion can be replicated in other contexts.

eLife Assessment

This study presents a useful theoretical model of molecular evolution of multi-copy gene systems by extending the classic Haldane model and applies the model to explain the surprisingly rapid evolution of rRNA genes. Although the conceptual model is intuitive and provides a new perspective for contextualizing this problem, the model presented does not adequately consider plausible biological constraints on the molecular and genetic processes. The lack of such constraints in the model, along with technical issues in the data analysis, provide incomplete support for the conclusion that the genetic variation patterns of rRNA genes in mouse is compatible with neutral evolution.

eLife Assessment

This study presents a useful model of genetic drift by incorporating variance in reproductive success, aiming to address several apparent paradoxes in molecular evolution. However, some of the apparent paradoxes only arise in the most basic version of standard models and have been reconciled in more advanced models. Nonetheless, this paper offers intuitive explanations for these apparent paradoxes, by adopting a new perspective and solid modeling and analysis. More broadly, the proposed model provides an alternative framework to address puzzling observations in molecular evolution, which will be of interest to evolutionary and population geneticists.

eLife Assessment

This important study of artificial selection in microbial communities shows that the possibility of selecting a desired fraction of slow and fast-growing types is impacted by their initial fractions. The evidence, which relies on mathematical analysis and simulations of a stochastic model, is compelling. It highlights the tension between selection at the strain and the community level. This study should be of interest to researchers interested in ecology, both theoretical and experimental.

eLife Assessment

This important study challenges conventional life-history theory by demonstrating that reproductive-survival trade-offs are minimal in birds, except when reproductive effort is experimentally exaggerated. The evidence is solid, drawing from a meta-analysis of over 30 bird species, and effectively separates the effects of individual quality from reproductive costs. The findings will be of broad interest to evolutionary biologists and ecologists studying life-history trade-offs and reproductive strategies.

eLife Assessment

This study maps the genotype-phenotype landscapes of three E. coli transcription factors and the topographical features of these landscapes. It shows that ruggedness and epistasis do not hinder the evolution of strong transcription factor binding sites. These convincing findings contribute valuable insights into fitness landscape theories and highlight the role of chance, contingency, and evolutionary biases in gene regulation. The authors then study the topographical features of these landscapes, especially the number and distribution of local maxima, as well as the statistical properties of evolutionary paths on these landscapes.

eLife Assessment

This study presents a potentially fundamental analysis of the original color of a fossil feather from the crest of a 125-million-year-old enantiornithine bird, using sophisticated 3D microscopic and numerical methods to conclude that the feather was iridescent and brightly colored, possibly indicating that this was a male bird that used its crest in sexual displays. At present, the strength of evidence supporting the authors' conclusions is considered incomplete based on methodological incompleteness and questions about taphonomy.

eLife Assessment

This is a valuable study of the role that life history differences might play in determining population size and demography. While concerns about generation times and population structure leave the evidence for the claims in parts incomplete, the work is of considerable interest to anyone who tries to understand evolutionary consequences of life history changes.

eLife Assessment

In this important study, the authors reconstruct the evolutionary history of a large and widespread group of freshwater fishes (Nemacheilidae) across Eurasia since the early Eocene, based on molecular phylogenetic analysis with very comprehensive samplings including 471 specimens belonging to 250 living species. The authors convincingly infer that range expansions of the family were facilitated by tectonic connections, favorable climatic conditions, and orogenic processes, adding to our understanding of the effects of climatic change on biodiversity during the Cenozoic. This work is of interest to evolutionary biologists, ichthyologists, paleontologists, and general readers.