Wild Wild Life newsletter: When species steal each other’s genes
Hello, and welcome to February’s Wild Wild Life, the monthly newsletter that celebrates the biodiversity of our planet’s animals plants and other organisms. To receive this free, monthly newsletter in your inbox, sign up here.
Spring in London is almost close enough to taste now, and the camellia, crocus and snowdrop blooms near our New Scientist office have been a testament to the city’s heat island. The first flowers of the year always seem to open a little earlier in central London than in its suburbs due to the higher temperatures of the urban environment. But earlier flowers aren’t just a city phenomenon – a study this month revealed that flowers in the UK are, on average, blooming a month earlier than they were before the mid-1980s due to climate change.
In this month’s newsletter, I’ll be taking a look at organisms that swap genes and what it means for evolution, plus a moth rediscovered in the Andes, a new finding concerning panda breeding, and how birds migrate.
New genes and where to get them
Now, here’s something surprising. Computational analysis suggests that a species of whitefly (Bemisia tabaci, pictured above) has acquired 50 genes from the plants they eat. No discovery like this has ever been made before, and while we don’t know how the genes got into the flies, there are signs that the genes are functional.
This particular story begins in March 2021, when a team published work revealing the first known case of a gene moving from plants into animals, in this same species of whitefly. The gene in question allows plants to store defensive toxins in a safe way, and the fly appears to use it to eat plants without being harmed by these toxins.
The finding suggested that horizontal gene transfer – the movement of useful DNA codes between entirely different species – may be much more widespread in the natural world than we suspected. Now, a different team has analysed the DNA of the whitefly to identify a full 50 genes that appear to have come from plants, and experiments suggest that many of them are used by the fly.
The really intriguing bit for me is: how did these DNA sequences move from the fly’s food and into its own genome? We don’t know, but we have some guesses. Perhaps viruses carried the genes into the flies, or perhaps it was transposons, which are regions of DNA that can move around and jump about the genome.
The mystery is even deeper for gene-swapping grasses. Last year, researchers looked at 17 species of grass and found that these species had transferred 170 genes between themselves. There was no evidence of hybridisation through reproduction, and these species don’t directly interact in the way that the whitefly and its food plants do. One idea is that wind pollination may somehow be involved.
I love anything that turns our understanding of genetics upside down, especially when there are implications for evolution. We’ve long known that bacteria swap genes – they do this mostly by sharing circles of DNA called plasmids with each other, a process that has had a big impact on us because this is how unrelated strains and species give each other antimicrobial resistance genes. The whitefly studies suggest that the species has found a use for at least some of the genes it has acquired from plants.
I’ll be interested to see in coming years if we discover that horizontal gene transfer has played far more of a role in the evolution of complex organisms than we thought. One of the crucial steps for evolution is: how can an organism get new genes? While this may appear a simple issue – mutations in our old genes create new ones that may be useful and shaped by natural selection – it isn’t usually so easy. What if you need all the genes you already have, and can’t afford to change some or give them over to new functions?
Decades of research suggest that the accidental duplication of genes – sometimes just of a handful of them, occasionally the entire genome – has historically provided life with additional genetic source material from which to fashion new innovations and adaptations. I wonder if horizontal gene transfer has enabled something similar, perhaps in a less dramatic and more frequent way.