New findings show how inherited and acquired genetic mutations cause breast cancer resistance to CDK4/6 inhibitors.

According to a new genomic study of Australia’s koala populations, rapid demographic rebound may be able to restore once-lost genetic variation and drive recombination in ways that re-establish long-term evolutionary potential in previously bottlenecked populations. Population bottlenecks can lead to evolutionary dead ends by eroding genetic diversity and intensifying inbreeding. Over time, these genetic repercussions can reduce fertility, survival, and resilience to environmental change, driving a so-called “extinction vortex” in which dwindling numbers and declining genetic health greatly amplify extinction risk. However, this genetic decline is not always irreversible. When populations rebound rapidly, their growth can sometimes restore genetic diversity. Theory suggests that ever-growing numbers – even in small founding groups – can promote genetic reshuffling and the introduction of new mutations, counteracting the loss of variation and easing the harmful effects of inbreeding. Thus, in theory, rapid demographic expansion may be a key mechanism for buffering against the genetic pitfalls typically associated with severe population declines. Here, Collin Ahrens and colleagues leveraged the precipitous decline – and the severe genetic bottleneck that resulted – and rapid rebound of koalas as a natural experiment to test whether population recovery was able to facilitate genetic recovery. Ahrens et al. used whole-genome data from 418 koalas drawn from 27 populations across Australia and found that, although koalas endured severe population decline and genetic bottleneck that left them with low genetic diversity, populations now show signs of genetic recovery. The findings suggest that this rebound may be driven in part by recombination, which shuffles existing genetic material into new combinations, helping to restore functional diversity as populations expand. Overall, the findings indicate that recovery of bottlenecked populations can occasionally occur through rapid population growth, which has important implications for conservation management strategies.

A unique Rubisco subunit from the hornwort plant carries a built-in extension that enables the enzyme to cluster into carbon-concentrating structures like algae, according to a new study – an innovation that successfully triggered similar condensates when introduced into Arabidopsis plants. The findings reveal a novel and evolutionarily independent solution for Rubisco condensation in land plants and open the door for engineering similar systems in agricultural crops to potentially boost nutrient efficiency and yield. Rubisco, or ribulose-1,5-biphosphate carboxylase/oxygenase, is the central enzyme responsible for carbon fixation in photosynthesis, but it also reacts with oxygen, leading to energy-wasting photorespiration. Many algae reduce this inefficiency by concentrating CO₂ around Rubisco inside specialized microcompartments called pyrenoids, which can dramatically boost local CO₂ levels and improve photosynthetic efficiency. This adaptation has received increasing attention, given its potential to increase yields in crop plants. Rubisco clustering is typically driven by specialized linker proteins that have evolved independently across lineages. However, these linkers often bind Rubisco in species-specific ways, and none of the known linker proteins are directly compatible with plant Rubisco, limiting their introduction to crop plants. Here, Tanner Robison and colleagues report the discovery of a distinctive variant of the Rubisco small subunit (RbcS) from the hornwort plant Anthoceros agrestis that provides a new solution to this challenge. According to Robison et al., this variant carries an ~100-amino acid extension at its C-terminal, termed the Sequestration Associated Region (STAR). Unlike previously known algal systems, which rely on separate linker proteins that bind Rubisco externally, RbcS-STAR appears to embed the condensation mechanism directly into the enzyme itself. In experiments, the authors show that attaching the STAR domain to native Arabidopsis RbcS was sufficient to trigger the formation of Rubisco condensates within chloroplasts. Further biochemical and structural analyses further revealed the molecular interactions that drive the assembly of these condensates. In a related Perspective, Moritz Meyer and Howard Griffiths discuss the study in greater detail.

Herpes simplex virus partially liquifies the tightly packed, gel-like interior of human cell nuclei to copy itself faster, a new study shows.

Researchers have developed an experimental “living eye drop” that uses naturally occurring eye bacteria to support corneal wound healing.

How does the brain process the complex flood of visual inputs? A new study at the University of Konstanz on larval zebrafish gives answers, combining behavioural experiments, advanced brain imaging and computational modeling.