Genetically modified livestock (GM livestock) are organisms from the group of cattle, sheep, pigs, goats, birds, horses and fish kept for human consumption, whose genetic material (DNA) has been altered using genetic engineering techniques. In some cases, the aim is to introduce a new trait to the animals which does not occur naturally in the species, i.e. transgenesis.
Video Genetically modified livestock
Terminology
Genetic modification is the direct manipulation of an organism's genome using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms.
Transgenesis is the process of introducing a gene from another species - called a transgene - into a living organism so that the organism exhibits a new property and transmits that property to its offspring.
Maps Genetically modified livestock
Pigs
In 2006, a pig was engineered to produce omega-3 fatty acids through the expression of a roundworm gene.
Enviropig was a genetically enhanced line of Yorkshire pigs in Canada created with the capability of digesting plant phosphorus more efficiently than conventional Yorkshire pigs. The project ended in 2012. These pigs produced the enzyme phytase, which breaks down the indigestible phosphorus, in their saliva. The enzyme was introduced into the pig chromosome by pronuclear microinjection. With this enzyme, the animal is able to digest cereal grain phosphorus. The use of these pigs would reduce the potential of water pollution since they excrete from 30 to 70.7% less phosphorus in manure depending upon the age and diet. The lower concentrations of phosphorus in surface runoff reduces algal growth, because phosphorus is the limiting nutrient for algae. Because algae consume large amounts of oxygen, it can result in dead zones for fish.
Cattle
In 1990, the world's first transgenic bovine, Herman the Bull, was developed. At the early embryo stage, Herman was genetically engineered in a laboratory by Gen Pharm International. Scientists micro-injected cells with the human gene coding for lactoferrin. The Dutch Parliament changed law in December 1992 to allow Herman to reproduce. Eight calves were born in 1994 following a breeding program established at Gen Pharm's European laboratory. All calves inherited the lactoferrin production gene. With subsequent sirings, Herman fathered a total of 83 calves.
In 2011, Chinese scientists generated dairy cows genetically engineered with genes from human beings to produce milk that would be the same as human breast milk. The researchers claim these transgenic cows to be identical to regular cows. Two months later, scientists from Argentina presented Rosita, a transgenic cow incorporating two human genes, to produce milk with similar properties as human breast milk. In 2012, researchers from New Zealand also developed a genetically engineered cow that produced allergy-free milk.
Researchers have developed GM dairy cattle to grow without horns (sometimes referred to as "polled") which can cause injuries to farmers and other animals. The process is called genetic editing. A short strip of DNA was taken from the genome of Red Angus cattle, where it is known to suppress horn growth, and inserted into cells taken from an elite Holstein bull called "Randy". Each of the progeny will be a clone of Randy, but without his horns, and their offspring should also be hornless
Goats
Goats have been genetically engineered to produce milk containing strong spiderweb-like silk proteins.
Fish
Salmon
In November 2015, the FDA of the USA approved the GM AquAdvantage salmon created by AquaBounty for commercial production, sale and consumption. It is the first genetically modified animal to be approved for human consumption. The fish is essentially a GM Atlantic salmon with a Chinook salmon (Oncorhynchus tshawytscha) gene inserted. This allows the fish to produce GH all year round for faster growth as the wild-type fish produces the hormone for only part of the year. The fish also has a second gene inserted from the eel-like ocean pout that acts like an "on" switch for the hormone. Pout also have antifreeze proteins in their blood, which allow the GM salmon to survive near-freezing waters and continue their development. The wild-type salmon takes 24 to 30 months to reach market size (4-6 kg) whereas the producers of the GM salmon claim it requires only 18 months for the GM fish to achieve this. It has been claimed that to prevent the genetically modified fish inadvertently breeding with wild salmon, all the fish will be female and reproductively sterile. However, it has also been claimed that a small percentage of the females will remain fertile. Some opponents of the GM salmon have dubbed it the "Frankenfish".
Triploid rainbow trout and largemouth bass
Genetically modified triploid fish have been used to stock waterways for angling. Triploid fish are sterile (wildtype are diploid) and therefore their metabolism is targeted to growth rather than reproduction. They grow to large weights making them attractive to anglers. In 2008, the US state of Washington bought more than 40,000 triploid rainbow trout (Oncorhynchus mykiss) and stocked them in 95 inland lakes to increase fish-license sales. Triploid largemouth bass (Micropterus salmoides), a fish which is keenly sought by anglers, have also been developed.
See also
- AquAdvantage salmon
- Tianjin animal cloning center
References
Source of article : Wikipedia
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