Why do we selectively breed animals and plants

Despite their physical dissimilarities, teosinte and corn only differ by about five genes. Today, corn is a staple in diets across the world. Averaged over the years from to , million tons of maize was produced each year around the world, primarily in the United States, China, and Brazil.

Without selective breeding, many of the plants and animals on earth today would not exist. However, there are some disadvantages of artificial selection, especially in the case of inbreeding.

Through inbreeding, two closely related organisms reproduce to yield a purebred with desired traits. However, these organisms may also have undesirable traits due to recessive genes found in both parents. Thus, purebred dogs are sometimes born with health defects like hip dysplasia and have shorter life spans than other mixed-breed dogs. Janssens, Luc, et al. Boyko, Adam R. Forest Service. Tigchelaar, Michelle, et al. Farrell, Lindsay L, et al. Actively scan device characteristics for identification.

Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. It also means that multiple genes can be identified at the same time. This makes it easier to select for traits controlled by several different genes, or to select organisms with a combination of different traits. However, even with these molecular tools, selective breeding can only get us so far.

In most cases, a trait can only be bred into a population if it already exists within a species. Therefore, selective breeding is limited by existing genetic variation. This is one reason why maintaining genetic diversity in nature is important: traits found in wild relatives can be bred into crop plants to help them respond to changing climatic conditions.

However, even if the gene for a desired trait is present in a population, and can be easily inherited, selective breeding is still a slow process because it requires selection over many generations.

It may also be difficult to separate target genes from less desirable ones. In other words, if an organism inherits the desired gene, it is very likely to inherit the less desirable one too.

Farmers have been tampering with the DNA of crops and livestock to improve their characteristics for thousands of years. Modern genetic techniques have made this process of selective breeding faster and more precise. However, even with these advances, selective breeding is still a slow process that takes place over many generations. Selective breeding is the traditional method for improving crops and livestock, such as increasing disease resistance or milk yield. Natural selection and selective breeding can both cause changes in animals and plants.

The difference between the two is that natural selection happens naturally, but selective breeding only occurs when humans intervene. For this reason selective breeding is sometimes called artificial selection. Different varieties of plants and animals with desired characteristics can be developed by selective breeding.

For example:. The new varieties may be economically important.