Articles in 2021

Analysing the global distribution, source and authorship of fossil research over the past 30 years, the authors find that researchers in high- or upper-middle-income countries hold a monopoly over palaeontological knowledge production, contributing to 97% of fossil data in the Paleobiology Database, leading to disenfranchisement of researchers in lower-income countries and biased spatial sampling across the globe.

Polymorphic duplicate genes are important early stages of duplicate gene evolution. Here, the authors characterize polymorphic gene duplicates with respect to dosage, exon–intron structures and allele frequencies for Drosophila and humans.

A model of pathogen evolution that allows for non-equilibrium dynamics finds that antigenic drift and escape select for the long-term persistence of more acute pathogens with higher virulence.

Tumour evolution modelling indicates that different tumour spatial structures can determine different tumour evolutionary modes, which are regulated by cell dispersal and cell–cell interactions. Model predictions of four evolutionary modes are consistent with empirical observations of cancers with varying architectures.

The authors investigate the broad-scale climatological and soil properties that co-vary with major axes of plant functional traits. They find that variation in plant size is attributed to latitudinal gradients in water or energy limitation, while variation in leaf economics traits is attributed to both climate and soil fertility including their interaction.

A combined modelling and tumour analysis approach is used to study the temporal and spatial patterns of subclone evolution in the TRACERx renal study. Studying the tumour shape and spatial features of clonal diversity in early-stage tumours may allow the prediction of tumour progression and patterns of subclone diversification over time.

The hunchback spider exhibits male-specific polymorphism in head shape. Here, the authors show that this polymorphism is determined by a large insertion that comprises duplicated male-specific genes including a duplicate of a key sexual differentiation regulatory gene.

Vertical transmission is thought to favour beneficial host–microbe interactions, but these may also be context dependent. Here Bruijning et al. show with a model that variable environments can select for bet-hedging by hosts via imperfect vertical transmission of microbes.

Based on an empirically estimated mutation rate, the authors show that the effective population size of Prochlorococcus, the most abundant carbon-fixing organisms in the ocean, is smaller than that of many free-living bacteria, suggesting an important role of drift in Prochlorococcus evolution.

Using a global analysis of 6,511 spoken languages with 51 predictor variables spanning aspects of population, documentation, legal recognition, education policy, socioeconomic indicators and environmental features, the authors identify predictors of current and future language endangerment and loss.

The Dox meiotic drive system distorts the sex ratio in Drosophila simulans. Here, the authors reconstruct the stepwise emergence, and recent amplification of Dox superfamily genes in parallel with the emergence of autosomal hairpin RNA-class siRNA loci that target subsets of these putative drivers.

Single-cell transcriptomics of hypothalamic cells from zebrafish and surface and cave morphs of Mexican tetra shows conservation of cell types and that cellular novelty is associated with genetic novelty and the species-specific expression of paralogous genes.

Identifying Neanderthal and Denisovan bone fragments using collagen peptide mass fingerprinting and mitochondrial DNA analysis at Denisova Cave, the authors are able to date the earliest secure Denisovan presence at the cave to c. 200 ka. The stratigraphic association with lithics and faunal remains allows the authors to explore the behavioural and environmental adaptations of these elusive hominins.

Measuring fitness effects of mutations in the same gene expressed at two levels, the authors show expression dependency of fitness effects in at least 42% of all single-nucleotide mutations, probably driven by avoidance of stochastic molecular errors.

Horizontal gene transfer could stabilize cooperation in bacteria because plasmids could promote the transfer of genes encoding public goods. However, the authors use comparative analysis and theoretical modelling to show that, while horizontal gene transfer may help cooperative genes invade a population initially, they have less of a role in long-term maintenance of cooperation.

In a long-running forest biodiversity experiment in China, the authors ask which measures of tree functional trait diversity impact productivity as forests develop. While productivity increased with community-weighted mean trait values early on, after 7 years productivity was significantly increased in plots with higher functional diversity.

Using natural hybrids between oviparous and viviparous common lizards, the authors describe the genetic architecture of parity mode and conduct a comparative analysis of genes associated with viviparity in mammals, squamates and fish.

Structural overshoot can occur when phases of excess plant growth deplete soil moisture too rapidly. The authors quantify structural overshoots using remote sensing datasets from 1981 to 2015, finding that 11% of droughts during this period could be attributed to structural overshoot.

The authors report a fossilized vertebrate rib with spiked dermal armour fused to its dorsal surface from the mid-Jurassic of Morocco, which they interpret as the earliest known ankylosaur.

The authors measure numerous ecosystem functions across an elevational gradient on Mt Kilimanjaro and find that species richness impacts function more than species turnover across sites. They also show that variation in species richness impacts ecosystem functioning more strongly at the landscape scale than at the local scale.