Selective breeding is the process of a breeder developing a cultivated breed over time and then choosing which ones are suitable enough to pass on to the next generation.

TYPES OF SELECTIVE BREEDING

IN-BREEDING - in-breeding is breeding between relatives, which results in a homozygous population. If this is practiced over time, it can lead to an in-breeding depression, which occurs when an in-bred individual shows lower health and fitness levels. Livestock breeders often practice inbreeding to “fix” desirable characteristics within a population.

LINEBREEDING – is a form of in-breeding. It is used by animal breeders to “fix” certain desirable traits, while leaving out the undesirable traits that happen in in-breeding. The mating of first cousins who share a common ancestor would be considered line breeding in the human race.

OUTCROSSING – the process of introducing genetic material into a breeding line. This creates genetic diversity, which greatly reduces the probability of gaining a genetic disorder. It is used in line breeding to restore size and fertility to a breeding line. Gregor Mendel used out crossing in his experiments with flowers in his breeding stock.

BENEFITS AND CONCERNS

BENEFITS – some benefits to selective breeding is that breeders get to choose which animals fit their criteria, so more of the right kind of animal can be produced, which makes more product. An example of this is dairy cows; a farmer wants cows that produce a lot of milk, not cows that don’t produce any. The farmers now have the ability to choose what cows they want to increase milk production.

CONCERNS – overuse of selective breeding can result in genetic disorders, such as inbred depression.