Finches sing to their eggs to reprogram their babies
The idea that an adult organism’s development is all pre-programmed in its genes, in a microscopic amount of DNA, is, when you think of it, stunning. But evidence has been emerging for some time that there is much more to it, with pre-birth environmental factors shown to influence the later adult in several ways.
For example, when the weather gets persistently hot, zebra finches incubating eggs give off special ‘heat-calls’ in the last one-third of the incubation period. Ingenious experiments have shown that this is what causes the baby birds to emerge smaller than others exposed to different maternal calls. Smaller size makes it easier to keep cool in the heat. In their later life, these birds were more successful at having offspring than those not exposed to heat calls within the shell.
Just how this happens is not clear, but more recent research suggests that it’s tied up with the function of mitochondria. These are the tiny ‘energy factories’ of the cell, which carry stretches of DNA of their own. These mitochondria are somehow ‘reprogrammed’ by the special sounds, which in turn makes the embryos grow more slowly and emerge smaller.
Since the parent birds obviously don’t understand what is happening, the fact that they ‘know’ when and how to change their songs must itself be a pre-programmed behaviour. All this is just one more example of the astonishing complexity of the masses of programmed information inside living things.
- Udino, E. and 6 others, Prenatal acoustic programming of mitochondrial function for high temperatures in an arid-adapted bird, Proc. R. Soc. B 288:20211893, 2021.
- Mariette, M. and Buchanan, K., Prenatal acoustic communication programs offspring for high posthatching temperatures in a songbird, Science 353(6301):812–814, 2016.
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