While the possibility for animals cloning has been realized for the last 25 years, this is only recently that adequate progresses have been made to permit the technology to move forward to a phase where it is potential that widespread commercial uses of cloning may turn into a reality in next few years. Although much has until now to be accomplished before farming of cloned animals and offspring of them become as familiar as GM plants are nowadays.
Cloning in the Dairy Industry
The actual word "cloning" refers to the production of a copy or copies of a creature, and occurs in the animals either artificially or naturally when an embryo is come apart to produce identical twins. It has therefore been adopted to explain the procedure of nuclear transfer that is used for production of a limitless number of genetically the same offspring. Therefore, cloning is just the generation of a genetic exact duplicate of the donor animal.
The procedure of Cloning for Dairying
The procedure of cloning first includes a method called enucleation, that entails removing the DNA or chromosomal genetic material from a adult oocyte (unfertilized female egg gathered from abattoir-derived ovaries, stored and frozen, then developed in vitro), and after that replacing that with genetic material of the donor animal to be duplicated. Enucleation involves manipulation of eggs with microsurgical tools under a microscope to physically eliminate the genetic material or chromosomes resulting in a cytoplast. The donor cell (that may be got from either embryos, adults, or fetuses, and grown in lab, and that may also be stored and frozen in liquid nitrogen and melted for use) is after that fused with enucleated oocyte and activated either with electrical impulse or chemically to induce reprogramming and activation of somatic cell genome to the embryonic genome.
Restructured cloned embryos are cultured for 5 to 10 days and transferred to uterus of a cow. About 40-50% of these restructured embryos develops to a point suitable for transfer to uteri of synchronized receiver cows and brings to term to create live cloned offspring. Approximately 10% result in birth of single live cloned calf. Therefore currently only about 5-6% of cloned embryos originally created actually make this to become calves.
Uses and Applications of Cloning in the Dairy Industry
A large number of studies have considered the application of cloning in cattle breeding and estimated its possible impact on the proportion of genetic progress.
This is generally agreed that cloning or nuclear transfer will have three key applications for farming, including
1. the production of GM (or transgenic) dairy cattle,
2. the rapid increase of animals with improved genetic characteristics, and
3. The use of cloning for selection of superior animals and phenotypic evaluation.
From a practical viewpoint, cloning could be applied to increase the distribution, number, and availability of bulls and cows with superior genetics for raised milk yield, increased availability of store with resistance to general diseases like mastitis, and enhanced availability of stock with wanted genetic traits related with milk quality. The additional development of transgenic will develop each of these functions.
Issues Associated with Dairy Cloning
Although cloning is commercially obtainable, the technology still is thought to be very costly and quite inefficient. Inefficiencies stem from micromanipulation of the oocytes and cloned embryos and culture of donor cells. This is due to huge number of abortions that happen during gestation. Additionally, when pregnancies actually development to term, gestation is generally comprehensive and calves are born larger than standard due to the large offspring syndrome that initiates dystocia, and most animals need cesarean section. These large offspring generally have hypoxia, postnatal weakness, hypoglycemia, hypothermia, and metabolic acidosis, all requiring urgent intensive care. Other issues that are sometimes related with the method include partial reprogrammation, reduction of telomeres, liver problems, kidney abnormalities, hypertension, and body and limb defects.
Another issue that requires to be considered cautiously is the potential that a lot of these postnatal troubles could be complicated from one generation to next. Obviously, any issue that would affect the capability of a cloned animal to make progeny that it selves can be cloned could develop into a serious obstacle in the set up of any selection plans. These issues are the largest barrier to current widespread application by the dairy industry. An additional potential issue with cloning is the probability of loss of the genetic diversity.
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