Dominic Wright states that the domesticated animals are in fact different from their wild counterparts. The difference is in the domesticated animals genetic makeup. These animals have differences in their physical and behavioral abilities. Domesticated animals tend to be smaller in …show more content…
Wright also discusses that the amount of genes, the effects of the gene size, and the location in the genome influence the different variations in a population. The major genes in an animal are accountable for the the vast majority of the different variations in a given trait. Most of the major genes are monogenic. This means that a single gene or mutation controls the questionable trait.
The author gives many examples on how this is possible. Some examples used are the domesticated animals; chickens, dogs, bovine, sheep, equine, and swine. Wright gives an example of a monogenic effect in chickens. He discusses the comb types, pea, walnut and rose mutations as an example to demonstrate an example of the Mendelian inheritance and epistasis in animals. These types of combs are only found in domesticated chickens, this has been identified at the genomic level. More monogenic traits in chickens are the yellow skin coloration, multi-pointed combs, and the barring coloration in the …show more content…
Such loci are present due to a powerful directional selection from domestication in these animals. Domestication could be an example of convergent evolution. It shows what happens to a species when there is a powerful directional selection within the species. An example of directional selection would be the behavioral effect of an animal being tame. Wright uses another animal example in the article. The silver fox shows evidence of that domestication can be recreated through selection lines. The selected traits were behavioral, these traits include tameness and aggression. After the study was done, Wright can conclude that after generations of the silver fox, that behavioral traits can lead to different morphological changes. This is evidence of pleiotropy in domestication. Wright explains that pleiotropy does exist in domesticated animals and that mutations often exist in connected groups of genes or mutations within the animals. Even though pleiotropic genes do exist, the effects from it are limited and cannot explain the large groups of different characteristics found in a