Write notes on transgenic cow
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In 1997, first transgenic cow, named Rosie, with human alpha-lactalbumin gene was produced. The milk of transgenic cow contained about 2.4 grams of human protein per litre of milk and was found to be more nutritionally balanced for human babies than that of natural cow milk.
Transgenic cows are genetically modified (GM) cows. They have an extra gene or genes inserted into their DNA. The extra gene may come from the same species or from a different species.
The gene construct is then introduced into female bovine (cow) cells by transfection. Transgenic bovine cells are selected and fused with bovine oocytes that have had all of their chromosomes removed. Once fused with the oocyte, the transgenic cell’s chromosomes are reprogrammed to direct development into an embryo, which can be implanted into a recipient cow. After a 9-month gestation period, a female calf is born. She will only express the transgene in her milk during lactation after her first calf is born. This is because expression of the transgene is controlled by a promoter specific to lactating mammary cells.
One of the aims of the research programme is to show that transgenic cows pass on their transgenes to subsequent generations. If a transgenic cow is mated with a transgenic bull, she will have a higher chance of having transgenic offspring. However, if a transgenic cow is mated with a non-transgenic bull, her offspring will have a 50% chance of being transgenic, as offspring inherit half of their chromosomes from their mother and half from their father.
Transgenic cows have a wide variety of potential applications in biomedicine, agriculture, animal health and environmental sustainability.