Living things must change their environment in one of two ways as the climate changes: geographically or genetically. While it’s moderately straightforward for researchers to track and record an animal variety’s geographic developments, demonstrating their hereditary variation after some time can be significantly more troublesome.
One of the first studies to document climate adaptation at the genomic level in a wild population is a new one published in Nature Climate Change by researchers at Colorado State University. The endangered migratory bird known as the Southwestern Willow Flycatcher, in particular, has demonstrated an increase in genetic variation associated with tolerance to environments that are drier and more humid.
Sheela Turbek, a postdoctoral scientist in CSU’s Branch of Science, drove this study that sequenced the genomes of the Willow Flycatcher over a 100- or more-year time span, contrasting DNA from historical center examples from the last part of the 1800s to present-day tests taken today.
“We scanned the genetic material for specific regions of the genome associated with important environmental variables using more than 200 recent samples from the Willow Flycatcher,”
Sheela Turbek, a postdoctoral researcher in CSU’s Department of Biology,
According to the findings of the study, the Willow Flycatcher population in San Diego, California, is better able to adapt to shifting climates thanks to an increase in genetic variation that began in the late 1800s.
Genetic adaptation to climate change Turbek hypothesized that wild populations would undergo genetic shifts as a result of the changing climate in San Diego, California, where weather conditions have gotten wetter and more humid over time.
“We used over 200 contemporary samples from the Willow Flycatcher to scan the genetic material for specific regions of the genome associated with important environmental variables,” Turbek stated. “We used these samples to scan the genetic material.”
Monthly maximum temperatures and precipitation are included in this. In both our historical and contemporary San Diego samples, we extracted the genetic information from the regions of the DNA that we believe are involved in climate adaptation.
Her research showed that Willow Flycatchers’ genetic variation has increased over time and that genetic regions associated with humidity and precipitation have both changed in a way that is consistent with climate adaptation.
Turbek, who works in Kristen Ruegg’s lab at CSU, picked up this research after Ruegg and collaborators had been working on a similar project for about ten years, demonstrating genetic adaptation over time. In the 2010s, significant advancements in the technology required to sequence entire genomes made this work possible.
Due to its endangered status, Turbek focused on the Southwestern Willow Flycatcher. The birds had localized and adapted to various climate conditions across space, as Ruegg’s preliminary research demonstrated.
According to Turbek, “The Willow Flycatcher is made up of four different subspecies, and the subspecies in the southwest has faced really precipitous population declines and was listed as federally endangered in 1995.” “The Willow Flycatcher is made up of four different subspecies.” Therefore, there is a great deal of interest from government agencies to effectively manage this subspecies and prevent its extinction as a result of climate change, which Kristen has demonstrated it may face in the future.
It is much more difficult to demonstrate genetic adaptation over time.
Decade-old samples frequently contain degraded, contaminated, or low-yield DNA, making it challenging to demonstrate genetic adaptation with sufficient certainty up until this point.
According to Turbek, “Museums will send us a little clipping from a toe pad that often has really low DNA concentrations, so it’s difficult to acquire enough reads of the DNA to have a good idea of what the genetic code looks like.”
The Willow Flycatcher’s genetic variation had increased over time, as the researchers discovered after years of sequencing the historical genome and comparing the results to modern samples.
According to Ruegg’s assertion, “We think that it was actually mixing or gene flow into the population from neighboring populations that helped recover the gene pool of the Willow Flycatchers in the San Diego area.”
Validating predictions regarding the effects of climate change Turbek and Ruegg are thrilled to be able to confirm scientists’ predictions regarding the manner in which certain species will adapt to climate change.
Turbek asserted, “Human-induced climate change is going to drive a lot of organisms to the brink of extinction.” This is because climate change has a significant impact on the reproductive activities of many species.
“Since these birds appear to be responding to the amount of climate change that has already occurred, the fact that we can document this amount of adaptation over a century-long time scale is somewhat encouraging. It can assist us in making better forecasts of what will occur in the future and how species might react.”
More information: Sheela P. Turbek et al, Historical DNA reveals climate adaptation in an endangered songbird, Nature Climate Change (2023). DOI: 10.1038/s41558-023-01696-3
