Domestication syndrome is a term that describes the permanent changes that appear in plants and animals as a result of domestication. These changes make these species different from their ancestors that were living in the wilderness. Plant crops are distinguishable from their ancestors because of this syndrome, and in animals, it is the cause of the development of many changes in looks and behavior.
Some of these behavioral changes include tameness and increased docility. The physical changes include the reduction in tooth size, coat color changes, changes in the forms of the ears and tail, and the shape of the face. There are other things that happen, such as many hormone changes and the extension of juvenile behavior. Also, brain size gets reduced.
The Origins Of The Syndrome
The domestication syndrome was explored by Charles Darwin when he tried to create a theory of heredity by observing animals and plants bred by humans. He managed to discover how animals that were domesticated had a specific set of traits. These traits were inheritable and were much different than any traits their counterparts in the wilderness possessed. He also found that domesticated birds and fish shared these traits. We usually name Darwin as the person who discovered domestication syndrome.
However, this syndrome has still not been properly explored to this day. Many explanations of it choose to focus only on particular traits while they neglect others, which also might be important. Other researchers focus solely on the selective factors that are present in the process of domestication but do not look at the genetic and developmental causes of all of these new traits. Some suggest that this syndrome is, for the most part, a result of deficits that develop in the neural crest cell while the animals are still in the form of an embryo.
The Research Of Charles Darwin
Scientists believe that most of the changes brought about by the domestication syndrome can be explained as being the consequences of these deficiencies in the neural crest. These changes can be either physiological or morphological. While most of them can be explained as direct consequences of the deficiencies mentioned earlier, some traits are indirect consequences of that same cause.
Charles Darwin did not deal with the theory of heredity in his seminal work “On the Origin of Species” from 1859. However, he was aware of its importance and started to explore it further in the following years. He offered a detailed study of the process of inheritance nine years later, in his work “The Variation of Plants and Animals Under Domestication.” The data he presented in this work was collected from various animal and plant breeders and was mostly based on observation.
Throughout this research, the phenomenon of domestication syndrome was discovered. Darwin explored how animal breeding worked, and he managed to discover all of the changes that occur throughout the domestication process. In the following decades, we were able to discover even more of the traits that develop in plants and animals, and thus the domestication syndrome was proven to be real.