Vadim Ghirda / AP

Many domesticated animals have several traits in common in a set known as "domestication syndrome," a term coined by Charles Darwin. It includes curly tails, floppy ears, childlike faces, small skulls, round snouts, and longer reproductive seasons. A trio of researchers and a four decades-long study in Siberia have narrowed down why these traits might be prominent in domesticated animals, and how they might be linked to genetics.

Floppy-eared fox study: The two researchers in Siberia hypothesized that the domestication process was linked to one trait: tameness, or acting less aggressive and more fearful of humans than was typical for their species. They also hypothesized that these traits were genetically linked.

  • The methods: Breeding the tamest foxes and observing trait development over time.
  • The results: Each subsequent generation was tamer than the last. Within 10 years of the study one fox pup exhibited floppy ears that never went away (most foxes maintain floppy ears for about two weeks in the wild). Many of the foxes at this stage in the study also exhibited other traits of domestication, supporting the hypothesis.
  • Go deeper in their article via American Scientist.

The genetic links: A trio of researchers thought tameness might be linked to the domestication traits through stem cells, known as neural crest cells, which migrate to different parts of the body when vertebrates are still embryos. The hypothesis is that tameness is linked with a smaller number of neural crest cells, which are linked to domestication traits.

  • They compared previous thinking on the matter, they present the hypothesis and propose genetic and evolutionary questions, and finally some predictions about what experiments could show.
  • Go deeper in their article via Genetics.

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