Editing Breeding back (section)

== Background ==
[[File:Rebuilding a Species.ogv|thumb|left|[[VOA]] report about the [[Quagga]] Project]]
The aim of breeding back programs is to restore the wild traits which may have been unintentionally preserved in the lineages of domesticated animals. Commonly, not only the new animal's phenotype, but also its ecological capacity, are considered in back-breeding projects, as hardy, "bred back" animals may be used in certain [[Conservation movement|conservation]] projects. In nature, usually only individuals well suited to their natural circumstances will survive and reproduce, whereas humans select animals with additional attractive, docile or productive characteristics, protecting them from the dangers once found in their ancestral environment (predation, drought, disease, extremes of weather, lack of mating opportunities, etc.). In such cases, selection criteria in nature differ from those found in domesticated conditions. Because of this, domesticated animals often differ significantly in [[phenotype]], behaviour and [[genetics]] from their wild forerunners. It is the hope of breeding-back programs to re-express, within a new breeding lineage, the wild, ancient traits that may have "lain buried" in the DNA of domestic animals.

In many cases, the extinct wild type ancestors of a given species are known only through skeletons and, in some cases, historical descriptions, making their phenotype poorly understood. Given that situation, there is currently no certainty of achieving success with a back-breeding attempt, and any results must be reviewed with great caution. In order to test genetic closeness, DNA (both [[mitochondrial DNA|mitochondrial]] and [[nuclear DNA|nuclear]]) of the breeding animals must be compared against that of the extinct animal.

Successful breeding back might be possible: humans have selected animals only for superficial traits, and as a rule did not intentionally change less-observable traits, such as metabolic biochemistry.<ref name="vanVuure"/>  Further, since many domestic species show  behaviours derived from their wild ancestors (such as the herding instinct of [[cattle]] or the social instincts of [[dog]]s), and are fit to survive outside the sphere of human interference (as evidenced by the many [[feral]] populations of various domestic animals), it can be presumed that "bred back" animals might be able to function like their wild ancestors.<ref name="vanVuure"/>  For example, food preferences are assumed to be largely the same in domesticated animals as in their wild type ancestors.

[[Natural selection]] might serve as an additional tool in creating "authentic" robustness, "authentic" behaviour, and perhaps, the original phenotype as well. In some cases, a sufficient predator population would be necessary to enable such a selection process; in today's Europe, where many breeding-back attempts take place, this predator population is largely absent.