Negatives Of Selective Breeding

Selective breeding is the human interference in the genetic transfer in animals and plants. Humans take the idea of natural selection where instead of the environment selecting for the alleles that are best suited for the organism to survive in the wild, humans select rare desirable phenotypic traits in organisms and breed them with each other in order produce an offspring containing those traits. Desirable traits include leaner meat in animals, or better quality milk in cows for commercial uses. The process is constantly repeated to the point where the frequency of the desirable allele increases in the genepool, and where the expression of the allele becomes homozygous. Humans use tests crosses and inbreeding to continue on developing the …show more content…
This is because of how common selective breeding occurs in organism which results in inbreeding depression. Inbreeding depression is when closely related species mate together. This is when the expression of deleterious mutations becomes high. Normally in natural selection, the frequency of deleterious alleles are reduced as the organisms are unlikely to survive. Most dominant deleterious alleles that are expressed can affect the organisms’ fitness and are less likely to survive in the wild hence the frequency of the deleterious alleles is low. However with recessive deleterious alleles, they are masked by their dominant allele counterpart which does not affect the organism’s health. Since selective breeding focuses on selecting specific traits, humans tend to chooses organism that are closely related to each other to create offspring’s expressing the desirable trait. If the desirable trait is recessive, this is when it can become a huge problem for organism, specifically …show more content…
Traits such as flat face or small head are considered desirable traits for some Pedigree dog breeds such as the Pug. Humans that breed closely related Pugs together are likely to carry the same deleterious recessive allele, meaning the offspring will inherit two deleterious alleles. The expression of the deleterious allele is harmful towards the Pugs health and survival because they suffer from all sorts of diseases. A common disease inherited over many generations of Pugs is the brachycephalic airway syndrome which impacts greatly on the health and survival of the pugs. Flat faced and small head trait, causes airway obstructions and respiratory distress. Pugs will require lots of medical attention to fix the health issues to increase its survival rate or will end up dying earlier than expected. If humans continue on with inbreeding, the survival of the Pug breed (or any dog breed in general) will die out. The expression of the deleterious allele can become so harmful for the breed that it would not even be able to survive.
Over the years as technology has improved, scientists have come up with a process using biotechnology to enhance the methods of selective breeding. Artificial insemination is an advanced method of selective breeding involving biotechnology. It is when a sperm taken from the male animal and is introduced into the uterus or cervix of the female animal. Just like with traditional selective breeding, humans