Species persistence following hybridization in nature requires the purging of introgressed alleles. Genomic monitoring of a tsunami-induced hybrid stickleback population in Japan reveals rapid genome-...

Evolution of genome architecture is increasingly recognized as a major driver of fungal adaptation. However, because most studies have focused on plant and human pathogens, the genomic mechanisms unde...

Abstract. Most biologically relevant traits are quantitative, controlled by multiple genes, and can be influenced by the environment. The multiple genes, c

Monarch butterflies, Danaus plexippus, in North America migrate south each autumn, but the mechanisms that initiate their migratory flight remain uncl…

Researchers have identified a previously unrecognised mathematical property that explains why one of evolutionary biology's most widely used statistical models can produce convincing but incorrect con...

Molecular Ecology is an international journal for research using molecular genetic techniques to address questions in ecology, evolution, behavior and conservation.

Abstract. Segmental duplications are major drivers of evolutionary innovation; yet, their dynamics across vertebrates remain poorly understood. Here, we id

Degenerate sex chromosomes ( e.g., the Y or W) remain among the most difficult regions of eukaryotic genomes to assemble because they are highly repetitive and structurally complex. While many recent ...

The germline-restricted chromosome (GRC) of the zebra finch Taeniopygia guttata represents a well-established model of programmed DNA elimination in vertebrates. Although the DNA composition of the GR...

Lancho-Silva et al. reveal two successive contacts between butterfly populations that capture the surprisingly rapid emergence of reproductive isolation driven by selection for chemical differences, a...

In Metazoa, transposon expression is suppressed by the piRNA pathway, and disruption of this pathway leads to rampant transposon expression. However, it remains unclear whether increased transposon ex...

Researchers found that the plants can identify caterpillar attacks and summon wasps to the scene to protect them.

Abstract. Habitat loss contributes to extinction risk in multiple ways. Genetically, small populations can face an ‘extinction vortex’—a positive feedback

Background Xenarthrans, comprising sloths, anteaters, and armadillos, represent one of the most morphologically and physiologically specialized mammalian clades, yet the genomic basis of their adaptations remains poorly understood. Here, we present chromosome-level genomes for the two-toed sloth (Choloepus didactylus) and the southern anteater (Tamandua tetradactyla) and investigate how retrotransposon-mediated gene duplications (retrocopies) have shaped genome evolution in these and other species in Xenarthra. Results Comparative analyses revealed that the xenarthran genomes analyzed here harbour the highest number of retrocopies reported among mammals, with lineage-specific insertion dynamics. Anteater and armadillo genomes contain older LINE1 repertoires and species-specific older retrocopy insertions. In contrast, sloths retain both an abundance of young LINE1s and thousands of young retrocopies, alongside a large shared set that originated from an evolutionary burst of retroduplication in the branch leading to their last common ancestor (~ 30 Mya). In C. didactylus, 49% of retrocopies were found to be expressed in five tissues, compared with 27% in Dasypus novemcinctus in three tissues. Evolutionary analyses identified 38 retrocopies with strong hallmarks of domestication in C. didactylus. Many of these retrocopies derive from parental genes involved in mitochondrial and metabolic processes, suggesting a potential genomic contribution to the physiological specializations of sloths. Conclusions Altogether, our findings identify retrotransposition as a major contributor to the genomic architecture of the xenarthrans presented here and highlight retrocopy origination as a mechanism for generating lineage-specific novelty and, possibly, distinctive biological specializations.

People are born with variable numbers of de novo germline mutations (DNMs), depending primarily on the ages of their parents. To explore additional causes, we developed an approach to call DNMs from nucleotide differences between siblings in genomic regions inherited identical by descent from both parents. Applying it to whole genome sequences from 28,985 sibling pairs of diverse genetic ancestries present in the UK Biobank and All of Us datasets, as well as 2,330 trios, we identified >800K autosomal DNMs and characterized mutation phenotypes in 27,645 sets of parents. We found subtle shifts in the mutation spectrum but no differences in total DNM rates among genetic ancestry groups, or between smokers and non-smokers. Testing for associations between parental mutation phenotypes and their burden of loss-of-function and deleterious missense variants in a set of 180 DNA repair and maintenance genes, we discovered that disruptions in REV1 and LIG1 increase germline mutation rates, and thus that rare mutator alleles segregate in population cohorts. ### Competing Interest Statement The authors have declared no competing interest. NIH, R35 GM083098

Abstract. Hybridization has many and varied impacts on the process of speciation. Hybridization may slow or reverse differentiation by allowing gene flow a

Abstract. European Lepidoptera have been subject of dense sampling for their DNA barcodes because of several active regional DNA barcoding initiatives. Thi

Post-glacial recolonisation of Fennoscandia created secondary contact zones in many species, offering opportunities to study how gene flow and selection contribute to their establishment and maintena....

Probabilistic models such as the sequentially Markovian coalescent have long provided a powerful framework for population genetic inference, enabli...

This review constitutes an evolutionary journey that begins with the emergence of reverse transcriptase and other ancient catalytic folds that shape retroelements (Class I transposable elements) and ends with the appearance of retroviruses and their subsequent or simultaneous endogenization. This path comprises milestones such as the formation of prokaryotic retroelements, their appropriation by eukaryotes, which resulted in the occurrence of non-long terminal repeat (non-LTR) retroelements, the mosaic formation of LTR retroelements by utilizing components of non-LTR retroelements and DNA transposons, and the acquisition of new domains that led to the emergence of retroviruses. We present here a comprehensive recounting of all evolutionary events that took place from the formation of primordial enzymes to the origin of retroviruses and their endogenization.

Off the coast of Japan, biologists netted a pea-size jellyfish with an unusual circadian clock — a chance finding that suggests there are likely more overlooked biological timekeeping mechanisms to…