Genetic modification in animals, also known as genetic engineering, involves intentionally altering an animal’s deoxyribonucleic acid (DNA) to introduce or modify traits. This technology aims to produce animals with desired characteristics not achievable through traditional breeding. It has been applied across various species for scientific investigation, agricultural improvements, and medical substance production.
Animals Modified for Research and Disease Understanding
Genetically modified animals play a significant role in scientific research, especially in understanding human diseases and developing new treatments. Scientists create animal models by altering specific genes to mimic human conditions. Mice are frequently used as research models, comprising over 90% of genetically engineered animals in research. For instance, mice can be modified to develop conditions such as cancer, Alzheimer’s disease, or cystic fibrosis, enabling researchers to observe disease progression and test potential therapies.
Beyond mice, other animals like rats and zebrafish are also genetically engineered for research. Zebrafish, with their transparent embryos and rapid development, are useful for studying developmental biology and genetic disorders. Altering genes helps pinpoint gene function and observe affected biological systems. This approach provides insights into disease mechanisms that are challenging to study in humans, contributing to medical advancements.
Animals Modified for Agricultural Enhancement
Genetic modification has been applied to livestock and aquaculture species to improve food production and farming efficiency. These modifications aim to enhance traits such as growth rates, disease resistance, and product quality. One notable example is the genetically modified AquaAdvantage salmon, engineered to grow faster than conventional salmon by incorporating a growth hormone gene from Chinook salmon and a promoter sequence from ocean pout. This allows the fish to reach market size in about half the time.
Pigs have been modified to resist certain diseases, such as porcine reproductive and respiratory syndrome (PRRS), which can reduce the need for antibiotics and improve animal health in agricultural settings. Similar efforts are underway to enhance disease resistance in other livestock. Modifications also focus on improving meat quality, altering milk composition, or increasing overall productivity in animals like cattle and sheep. These advancements can lead to increased food production and improved nutrition.
Animals Modified for Medical and Pharmaceutical Applications
Animals are also genetically engineered to produce medical substances or for use in transplantation procedures, a process sometimes called “pharming.” This involves modifying animals to act as living bioreactors, producing therapeutic proteins or other valuable compounds. For example, goats have been genetically engineered to produce human proteins, such as antithrombin, in their milk, which can then be purified and used as pharmaceuticals. Chickens have also been modified to lay eggs containing specific therapeutic proteins.
Another significant application is xenotransplantation, which involves transplanting cells, tissues, or organs from animals into humans. Pigs are a primary focus for xenotransplantation research due to their organ size and physiological similarities to humans. Scientists are genetically modifying pigs to reduce the risk of immune rejection when their organs are transplanted into human recipients. This research aims to address the shortage of human organs available for transplantation.
Other Notable Genetically Modified Animals
Beyond research, agriculture, and medicine, genetic modification has yielded other notable animal applications. One publicly recognized example is the GloFish, a pet fish genetically engineered to fluoresce under ultraviolet light. These fish contain genes from jellyfish or sea anemones, giving them vibrant colors that are not naturally found in their species. Initially developed for environmental monitoring, they were later marketed as ornamental pets.
Mosquitoes have also been genetically modified for pest control and to reduce the transmission of diseases like dengue fever and malaria. These modifications often involve introducing genes that cause sterility in the mosquito population or make them less capable of carrying and transmitting pathogens. These applications showcase the diverse and evolving ways genetic modification technology is being explored and utilized in the animal kingdom.