Beijing, April 1 (Reporter Sun Zifa) - A genetics paper published in Communications Biology, a peer-reviewed journal under the Springer Nature umbrella, has unveiled a study showing that the social status of wild female spotted hyenas (Crocuta crocuta) is mirrored in their genome-wide DNA methylation patterns. DNA methylation involves the addition of methyl groups to the DNA, altering gene expression patterns without changing the DNA sequence itself.
The paper reveals that hyenas establish social hierarchies, with higher-ranking females dominating lower-ranking ones and maintaining this order across generations, with adult females passing their status on to their daughters. Prior to this study, it was unclear whether the social status of hyenas was reflected at the molecular level in both cubs and adult females.
In the Serengeti National Park in Tanzania, spotted hyenas take a communal rest (photo by Sarah Benhaiem). Courtesy of Springer Nature
Researchers led by Alexandra Weyrich from Leipzig University in Germany, along with colleagues, analyzed DNA extracted from 42 fecal samples of spotted hyenas from the Serengeti National Park. Among these samples, 18 were from high-ranking females (9 adults and 9 cubs), while 24 were from low-ranking females (9 adults and 15 cubs).
Their study revealed that 149 genomic regions exhibited differential methylation levels between high-ranking and low-ranking hyenas. Additionally, they found that methylation levels were higher in low-ranking adult hyenas and high-ranking cubs. Among these regions, 44 contained genes primarily associated with energy conversion, immune system function, ion transmembrane transport, and a critical signaling pathway (the glutamate receptor signaling pathway) for the gut-brain axis.
The researchers infer that these methylation differences in genes may be due to the lower ease of food acquisition for low-ranking females compared to high-ranking ones, leading them to engage more frequently in long-distance foraging, potentially resulting in compromised immune responses. After training a predictive tool based on DNA methylation patterns to estimate social status, they found that these 149 genomic regions could predict hyena social status with an accuracy of 80%.
In conclusion, the authors of the paper suggest that the findings of this study collectively indicate that the social status of wild female spotted hyenas, both adults and cubs, is reflected in specific patterns of DNA methylation. Further research is needed to investigate the potential physiological consequences of these DNA methylation patterns.
