Domestication

ANS 151

What are the 2 processes of domestication

• cultural

• biological

Biological Domestication

resembles a form of genetic selection in that the parent animal (first one domesticated) becomes isolated from the wild population

• results in genetic drift from its wild ancestors, either active or passive

Cultural Domestication

changes in how the animal becomes included in the social structure of human societies.

• what role does it play in its interaction with humans

Symbiosis

All conditions of permanent living together of two different species

• domestication is a form of this

Guest and Host

Guest is the subordinate partner and the Host is the dominant partner

Perfect Symbiosis

when both partners derive equal benefits, without domination by one of the partners

• there is so subordinate or dominate

• VERY rare

Domestication Hypothesis

• Dmitry Belyaev

• hypothesis that the primary factor selected for during domestication was a behavioral trait which he called “tamability”

Belyaev argued that “Tamability” was…

•  a innate behavioral trait that all animals possessed 

•  within any population of animals there was variation in its expression.

• • could be selected for (in much the same way breeders select for coat color, etc.)

• it was controlled by “higher order” genes (genes that controlled other traits).

In other words, if one selected only for “Tamability”, then other phenotypic changes would occur.

phenotypic traits associated with domestication

• blazed forehead

• curled tail

• floppy ears

• piebald coat

Belyaev’s Experiment

• Wild population of foxes

• Devised a way to select for “tamability”

• Separated the foxes into classes I-III (Most domesticated to least)

• determined the classes by sticking his hand in the cage and noting how they reacted to it

• he then allowed the foxes to breed within their own “tamability” group

• After 20 generations, he observed many of the phenotypic changes that he predicted.

Class IE

“Domesticated elite” Eager to establish human contact. Whimper to get attention. Lick or sniff experimenters.

Phenotypic Changes

• Dwarf and giant breeds

• Piebald coat color

• Blazed Forehead

• Floppy Ears

• Curled Tails

• Wavy or Curly Hair

Physiological Changes

• Breeding Season (become less seasonal with domestication)

• Fertility (become more fertile with domestication)

• Hearing age (age at which animals can first hear increases as they become more domesticated)

• Sight age (age at which animals can first see increases as they become more domesticated)