Repeated evolution of similar traits in organisms facing the same ecological challenges has long captured the interest of evolutionary biologists (1–4). Naturally occurring examples of "convergent evolution" offer new opportunities to ask about predictability in evolution. Do complex genomes mean that there are endless possibilities for adapting to an ecological challenge? Or must evolution target the same genes, or even the same amino acids in the same proteins, in order to increase the fitness and therefore survival of different species facing similar challenges? Natarajan et al. (5), on page 336 of this issue, provide an example of an integrated approach to answer these questions.
Because evolution usually takes many generations, it is hard to tell. But two new genetic studies reveal DNA changes that took hold within the last few thousand years, suggesting that modern lifestyles have recently shaped our evolution – and are probably still doing so. "During a short time, human genomes have changed a lot," says Irina Morozova of the University of Zurich in Switzerland. "We think these changes are driven by human civilisation."
WHAT kind of force is evolution? You may see it as malevolent, benevolent or both, but chances are you will also think of it as monumental – long-term and large-scale. Over billions of years, evolution has created life on Earth from the giraffe's neck to an ape clever enough to contemplate how life evolves. Yet evolution can also be fast and furious. It is happening right here, right now – and it threatens the very future of civilisation (see "Outsmarting evolution: Fighting a force that threatens civilisation").
Pokémon Go players have bemoaned the rarity of evolution items for some time now, and new evidence from the Silph Road subreddit suggests Niantic may have heard those concerns. Over the last 24 hours, finding Dragon Scales, Metal Coats and other hidden treasures has never been easier. While only one evolution item was previously guaranteed for stopping at the same PokéStop for a week straight, a user by the name of Thermocap recently noticed yields much higher than that. On the seventh day, a single spin offered an Upgrade, King's Rock and Dragon's Scale. It turns out this player wasn't the only lucky one either.
The field of molecular evolution is concerned with evolutionary changes in genes and genomes and the underlying driving forces behind those changes. Current studies in molecular evolution are almost entirely retrospective, with a focus on the mutations that were fixed during evolution, and the conclusions are often explanatory, offering no predictive insights. Because only a tiny fraction of all mutations that have ever occurred during evolution have been fixed, the "successes" that we see today provide an incomplete or even biased understanding of the evolutionary process. One way to circumvent this problem is to obtain the whole fitness landscape of a gene to understand, prospectively, chance and necessity in evolution (see the figure).