Do you know the concept of phenotypic plasticity? Beyond their genes, this would allow organisms to “remember” their ancestral environment.
According to a study recently published in Science Advances, gallinaceans retain a genetic memory of their past adaptation to their environment.
Chickens keep the memory of their ancestors
What if the hens remembered the environment in which their ancestors once lived thousands of years ago?
Chickens brought to altitude in Tibet
This is what a team of researchers wanted to verify by giving birth to hundreds of hens and dividing them into four groups to subject them to specific environments. The results of this study, involving researchers from the University of Michigan and the Agricultural University of Sichuan, were published in the journal Science Advances.1
Gallus gallus domesticus (Chicken) was brought to the Tibetan plateau about 1,200 years ago. But it was actually domesticated 4,000 to 4,500 years ago in South and Southeast Asia. The researchers have therefore grown chickens accustomed to the plains on the Tibetan plateau, as well as in their usual plains of life. And, conversely, hens accustomed to the Tibetan plateau have been raised in the plains as well as in their current environment.
The concept of phenotypic plasticity
The idea pursued by these researchers: when the men brought the chickens with them, they had to adapt to the Tibetan highlands. But they would have in fact kept this evolution in memory, which would help them to readjust more easily to environments already known by the species in the past.
Thus, the golden rooster had to increase its amount of red blood cells in order to carry oxygen in order to adapt to high altitudes. A modification, an adaptation not part of his genes, but actually preserved in a kind of “genetic memory”. As Jianzhi Zhang, the study’s lead co-author and professor of evolutionary ecology and biology, explains, is talked about phenotypic plasticity induced by the environment.
In other words, once a species has adapted to its new environment, it remains so forever. Example of this phenotypic plasticity: on the shelf, the eggs of plains hens have hatched less than those of high-altitude hens. In contrast, the eggs of high-altitude hens have hatched as much as those of plains hens. When the plains hens had to adapt to the Tibetan plateau, those accustomed to altitude used to their phenotypic plasticity to remember the time when their ancestors lived in the plains.
Thus, for these researchers, their results show that “organisms generally ‘remember’ their ancestral environment through phenotypic plasticity.” This long-term memory improves their adaptation to changes in their environment, and underlines the importance of whether a species is in a new or ancestral environment. Ref: Science Advances