Culture May Shape Genetic Makeup in Dolphins
Social behavior can change a person's genetic makeup, a new study on dolphins suggests.
Researchers from the University of New South Wales looked at bottlenose dolphins that use sponges as tools and found that social behavior can shape the genetic makeup of an animal population in the wild.
Previous studies reveal that some dolphins in Shark Bay in Western Australia put conical marine sponges on their rostrums (beaks) when they look for food on the sea floor. Researchers said this is an example of a non-genetic skill that calves apparently learn from their mother.
However, the latest study reveals that sponging dolphins end up with some genetic similarities because the calves also inherit DNA from their mothers. Researchers also believe that that sponging dolphins are offspring of a "sponging Eve", a female dolphin that first invented "sponging".
"Our research shows that social learning should be considered as a possible factor that shapes the genetic structure of a wild animal population," said lead author Dr Anna Kopps.
"It is one of the first studies to show this effect - which is called cultural hitchhiking - in animals other than people," she added.
Researchers collected genetic samples from individual dolphins in western Shark Bay about 850 kilometers north of Perth. Researcher also monitored the dolphins from a boat to see how they foraged for food, swam around the bay, rested and played with other dolphins.
After analyzing from mitochondrial DNA type, which is only inherited from the mother, researchers found that the dolphins living in shallow waters, where sponges do not grow, mainly fell into a genetic group called Haplotype H. However, those that lived in deep waters, where sponges grow, were mostly Haplotype E or Haplotype F. The findings also revealed that DNA analysis from 22 dolphins that both lived in deep water and used sponges as tools showed they were all Haplotype E.
"This striking geographic distribution of a genetic sequence cannot be explained by chance," said Kopps.
"For humans we have known for a long time that culture is an important factor in shaping our genetics. Now we have shown for the first time that a socially transmitted behavior like tool use can also lead to different genetic characteristics within a single animal population, depending on which habitat they live in," she concluded.