Why domestication makes animals tamer

Domestication primarily involves small changes in many genes controlling the development of the brain and the nervous system, leading to behavioural changes in animals, showed a study that looked into rabbit domestication.

"The results we have are very clear; the difference between a wild and a tame rabbit is not which genes they carry but how their genes are regulated i.e. when and how much of each gene is used in different cells," explained Miguel Carneiro from University of Porto in Portugal.

In contrast to domestic rabbits, wild rabbits have a very strong flight response. The scientists first sequenced the entire genome of one domestic rabbit to develop a reference genome assembly.

Then they resequenced entire genomes of domestic rabbits representing six different breeds and wild rabbits sampled at 14 different places across the Iberian Peninsula and southern France.

The team observed very few examples where a gene variant common in domestic rabbits had completely replaced the gene variant present in wild rabbits; it was rather shifts in frequencies of those variants that were favoured in domestic rabbits.

An interesting consequence of this is that if you release domestic rabbits into the wild, there is an opportunity for back selection at those genes that have been altered during domestication because the 'wild-type' variant has rarely been completely lost.

"We predict that a similar process has occurred in other domestic animals and that we will not find a few specific "domestication genes" that were critical for domestication," Leif Andersson from Uppsala University in Sweden noted.

The domestication of animals and plants, a prerequisite for the development of agriculture, is considered one of the most important technological revolutions during human history.

The study appeared in the journal Science.