Climate change heating the genetic landscape: How temperature is stressing out DNA
- Nikolas Dzamba
- Mar 22, 2023
- 3 min read
By: Nikolas Dzamba
Climate change heating the genetic landscape, how temperature is stressing out DNA One of the main causes of DNA damage is harmful exposure of heat from the sun and this has become an increasingly important topic due to the rise in temperature from climate change. Although DNA is able to repair and regrow, when there is too much damage d one it can lead to premature aging and debilitating diseases such as cancer. Ursula Beattie and her team (2022) began to investigate how higher temperatures seen during the summer and spring months might be causing increased DNA damage in house sparrows compared to the winter months. Currently, glucocorticoid and catecholamine release are seen as the baseline for testing stress on an organism. These are two hormones released during the “fight or flight” response often seen during stressful times, but Beattie and her colleagues believed DNA damage provided a broader view of biological stress due to its integration between the organism and its environment. This was the inception of their study and allowed them to complete the experiment on the house sparrow.
The researchers began their experiment by gathering 31 house sparrows divided amongst different groups. To simulate the different seasons each group was placed through different light/dark cycles as there is less light during winter months and more during summer. After these cycles were complete the birds had blood drawn as well as samples from their hippocampus, hypothalamus, stomach fat, and liver. The hippocampus and hypothalamus were sampled due to them being the main source of stress response in the brain, the liver was chosen as glucocorticoids and catecholamines travel through it by blood. Each of the samples were prepared and placed on slides to have the DNA tested using comet assay. Comet assay is a method of examining DNA damage combining living cells with detergents that break open the cell and let the DNA unwind for our viewing!
Many results were yielded from this experiment. Beattie and her team found that blood samples from the house sparrow were indicative of the same DNA damage as the other tissue types. This tells us that future research involving DNA damage can be done by simply taking a blood sample and not having to kill these animals for tissue samples. Another piece of the results puzzle was whether captivity affected the level of DNA damage. The researchers found that both captive and free-living birds have no significant change to their DNA damage, meaning they experienced similar results. Lastly, the researchers wanted to find out if there was a difference in DNA damage over seasons. They found that indeed, there was a significantly higher level of DNA damage seen during the summer months rather than the winter months.
Overall, it was found, by the work of Ursula Beattie and her team, that there is a higher level of DNA damage during the summer months. They also were able to conclude that habitat did not matter for DNA damage as the captive and free-living birds experienced the same level of DNA damage. This is a highly recent and impactful study as it highlights the problems that the Earth is facing with climate change. Heat stress is a massive cause of DNA damage and if the planet continues to warm, we could see this stress causing problems for all living life. This study also impacts methodology as they produced an increasingly humane way to test for DNA damage using blood samples. Not only was this paper valuable in itself, it also offers new avenues of study for future research. It is known that UV radiation from the sun causes most DNA damage, but these house sparrows have feathers covering their entire body. How then could there be higher DNA damage just due to a change in daylight? Hopefully these questions, and more, will be answered soon.
Comments