Wei-Guo Du, Yang Wang, Shu-Ran Li, Zhi-Gao Zeng and Liang Liang
It has long been known that the environment experienced by a mother can affect offspring traits without modification of the DNA sequence. This phenomenon of maternal effect would be adaptive when mothers can adjust the phenotype of their offspring to match the changes in the local environment, as suggested by the “environmental matching hypothesis”. On the other hand, it will be detrimental when the conditions of mother and offspring are mismatched. For example, a mismatch of nutrient conditions in humans between fetus (e.g. nutrient-poor conditions due to maternal food shortage) and adults (e.g. nutrient-rich conditions) may lead to a disorder of energy utilization and storage, and in turn to cardiovascular diseases and type 2 diabetes. However, this widely-accepted hypothesis has not been rigorously tested.
We conducted a full factorial experiment on maternal and offspring food conditions (high vs low food availability) to explore the adaptive significance of maternal effects induced by food availability in a lizard from the desert steppe of China. We found offspring of food-restricted mothers had higher growth and survival rates than those of food-unrestricted mothers, regardless of food availability for offspring. Unexpectedly, these findings do not support the “environmental matching hypothesis”, but instead suggest that offspring of food-restricted mothers have better performance under all offspring food conditions, to compensate for a bad start (low-food condition) to their lives.
Image caption: Lizard. Photo provided by authors.