AsianScientist (Mar. 19, 2025) – Despite their bamboo-based diet, giant pandas have the digestive system of a carnivore. Outwardly, pandas are well adapted for eating bamboo, with pseudo-thumbs to help them hold the stems, and strong jaws with flat teeth to crush them. But while most herbivorous mammals have elongated intestines to better digest tough plant material, pandas do not. This suggests that pandas were once carnivores but transitioned to eating plants.
In a study published in Frontiers in Veterinary Science, researchers from China looked into the possibility that genetic material from bamboo could be helping pandas adapt to their diet.
MicroRNA (miRNA) is a form of non-coding RNA that regulates gene expression. They can bind to messenger RNA, which transmits the information stored in DNA, to suppress or activate gene functions. Plant miRNA is extremely resistant to degradation, able to pass through the mammalian digestive system and be absorbed into the bloodstream unaltered.
“We showed that plant-derived miRNAs are present in the blood of giant pandas,” said Feng Li, a researcher at China West Normal University and senior author of the study. “Our study proved that bamboo used as food for giant pandas does affect the change of giant pandas’ feeding habits.”
The researchers analysed blood samples from seven giant pandas – three adult males, three adult females, and a juvenile female, and found 57 miRNAs that likely originated from bamboo.
“MiRNA in bamboo can enter giant pandas’ bodies through diet, be absorbed by the intestine, enter the blood circulation, and then regulate when the giant panda’s RNA transfers information, thus playing a role in regulating the gene expression of giant pandas,” Li explained.
“MiRNA in bamboo is also involved in the regulation of smell, taste, and dopamine pathways of giant pandas, all of which are related to their feeding habits,” Li said. One of the miRNAs the researchers identified regulates the TAS2R3 gene, making pandas more sensitive to bitterness. This is an advantage in avoiding bamboo containing toxins.
MiRNA that regulates genes related to pandas’ sense of smell enables them to identify the freshest and most nutritious bamboo. The researchers believe that miRNA accumulates as pandas grow older and eat more bamboo, helping them adapt further to their diet.
Bamboo miRNA was also found to influence other physiological processes in pandas. Different miRNA compositions were found in pandas of different sexes, related to their respective reproductive processes. “Only miRNAs that can specifically play a role in regulating gene expression can remain in the body, and those that do not play a role will be expelled,” explained Li. As miRNA can both suppress and activate genes, the researchers are unsure if bamboo miRNA has mitigated the panda’s low reproductive capacity, or contributes to it.
These findings open up new avenues of research into the giant pandas’ dietary shift, as well as providing further knowledge of miRNA’s ability to transfer from plants to animals.
“The giant panda is a very precious national treasure in our country, and blood samples are not easy to get,” Li shared. “If possible, we hope to collect blood samples of young pandas who have not yet eaten bamboo for research, and perhaps get more surprising results.”
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Source: China West Normal University ; Image: Shutterstock
This article can be found at Cross-kingdom regulation of gene expression in giant pandas via plant-derived miRNA
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