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Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together.
The existence of limits in artificial selection experiments was discussed in the scientific literature in the 1940s or earlier. [1] The most obvious possible cause of reaching a limit (or plateau) when a population is under continued directional selection is that all of the additive-genetic variation (see additive genetic effects) related to that trait gets "used up" or fixed. [2]
Heck cattle were bred in the 1920s to resemble the aurochs.. Breeding back is a form of artificial selection by the deliberate selective breeding of domestic (but not exclusively) animals, in an attempt to achieve an animal breed with a phenotype that resembles a wild type ancestor, usually one that has gone extinct.
Therefore, only those with the highest index score are selected for breeding via artificial selection. This method has advantages over other methods of artificial selection, such as tandem selection, in that you can select for traits simultaneously rather than sequentially. Thereby, no useful traits are being excluded from selection at any one ...
Tandem selection is a method of artificial selection in which useful traits are selected for sequentially. [1] For instance, one could select for both increased milk yield and increased milk fat content in cows via tandem selection by first selecting those with the best of one trait, production of high milk yield, and then when that trait is at a satisfactory level, by starting to select for ...
Human intervention through artificial selection of animals with desirable characteristics further increased the differentiation among and uniformity within breeds. Examples of traits that have been deliberately selected by humans include growth rate, milk or egg production, coat color, meat quality, and age of maturity, among many others.
The red junglefowl (Gallus gallus), often believed to be an ancestor of the domestic chicken.. Most animals are tuned to modern life by artificial selection. This is either due to the pressure of early hunter-gatherers' attempts to stabilise the food supply, which resulted in the existence of domesticated farm animals, or domestication of pets which are useful to humans. [2]
Examples are the cabbage varieties, maize, or the large number of different dog breeds. The power of human breeding to create varieties with extreme differences from a single species was already recognized by Charles Darwin. In fact, he started out his book The Origin of Species with a chapter on variation in domestic animals. In this chapter ...