Adaptive genetic variation has been thought to originate primarily from either new mutation
or standing variation. Another potential source of adaptive variation is adaptive variants from …

Mutational input is the ultimate source of genetic variation, but mutations are not thought to
affect the direction of adaptive evolution. Recently, critics of standard evolutionary theory …

Studies of the genetic basis of adaptive changes in natural populations are now addressing
questions that date back to the beginning of evolutionary biology, such as whether evolution …

Populations adapt to novel environments in two distinct ways: selection on pre-existing
genetic variation and selection on new mutations. These alternative sources of beneficial …

There has been recent progress in identifying selective sweeps underlying a range of
adaptations. Jonathan Pritchard and Anna Di Rienzo argue that many adaptive events in …

Background Whether natural selection can erase the imprint of past evolutionary history from
phenotypes has been a topic of much debate. A key source of evidence that present-day …

Patterns of local adaptation are expected to emerge when selection is spatially
heterogeneous and sufficiently strong relative to the action of other evolutionary forces. The …

Convergent evolution of similar phenotypic features in similar environmental contexts has
long been taken as evidence of adaptation. Nonetheless, recent conceptual and empirical …

Biologists often distinguish 'convergent'from 'parallel'evolution. This distinction usually
assumes that when a given phenotype evolves, the underlying genetic mechanisms are …

Evolutionary biologists have long been interested in the conditions favoring phenotypic
plasticity, in which a single genotype produces alternative phenotypes in response to …