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Cloning is a scientific process that produces genetic copies of animals by replacing the nucleus of an unfertilized egg cell with the nucleus of an egg cell drawn from another organism. The altered egg, which is then considered "fertilized," is planted into the womb of a host animal; the offspring resulting from this pregnancy will be an exact genetic replica of the organism that provided the replacement nucleus. Recently, cloning has been used to generate animal populations for the purpose of food production. Despite several benefits, this practice—known as clone harvesting—has proven to be controversial.
Meat and dairy industries can use cloning technologies to produce exact genetic replicas of the healthiest and most fertile cows and bulls. After the first successful cloning of a mammal in 1996, cloning technology in livestock production progressed at an aggressive pace and cloning, as a result, soon became one of the most popular alternative breeding techniques. Because cloning livestock is expensive, clones are generally not slaughtered for meat; instead, they are used to produce superior offspring for mass food production. Research groups are working on genetically engineering cattle that could produce insulin-containing milk for people who suffer from diabetes, or livestock whose meat could release clotting factors that would prove useful in treating patients with hemophilia. Because conventional breeding does not guarantee that genetic modifications will transfer to offspring, cloning is necessary to replicate these modifications.
In 2001, however, in response to observations that cloned animals are sometimes born sickly, deformed, and beset with neonatal diseases, the federal Food and Drug Administration (FDA) demanded a moratorium on the sale of food products derived from animal clones and their offspring until further research could be conducted. Scientists then determined that the majority of neonatal problems in clones arise from epigenetic, or environmental, factors. Because such problems are not DNA-based, cloned animals are unlikely to transfer them to their offspring. The FDA wisely lifted this moratorium in 2008, concluding that the risk of consuming products from cloned sources was no higher than that of consuming products from non-cloned sources. Furthermore, scientists discovered that deformities occur at similar rates when other alternative breeding techniques, such as embryo transfer and in-vitro fertilization, are employed.
Detractors of animal cloning point to the potential for unanticipated problems associated with the reduction of biodiversity in livestock breeding pools that results from the cloning process. A herd of clones bred from a single animal is highly vulnerable to contagious disease, because an animal's offspring tends to possess the same immunities as its progenitors, and a cloned animal has only one progenitor. Because the long-term environmental consequences of such practices have not been investigated, some argue that the FDA should reissue the moratorium. Moreover, many remain deeply uncomfortable with cloned meat; over 70% of consumers claim in surveys that they would not knowingly consume cloned animal meat.
The primary purpose of the passage is to
(A) argue against the use of cloning technology in commercial livestock production.
(B) define cloning and summarize recent technological developments in animal cloning.
(C) provide examples of medical problems that have the potential to be solved by livestock clone harvesting.
(D) explain why the FDA imposed a moratorium on the use of animal clones and their offspring in food production.
(E) discuss the advantages and disadvantages of animal clone harvesting and their impact on policy.
Meat and dairy industries can use cloning technologies to produce exact genetic replicas of the healthiest and most fertile cows and bulls. After the first successful cloning of a mammal in 1996, cloning technology in livestock production progressed at an aggressive pace and cloning, as a result, soon became one of the most popular alternative breeding techniques. Because cloning livestock is expensive, clones are generally not slaughtered for meat; instead, they are used to produce superior offspring for mass food production. Research groups are working on genetically engineering cattle that could produce insulin-containing milk for people who suffer from diabetes, or livestock whose meat could release clotting factors that would prove useful in treating patients with hemophilia. Because conventional breeding does not guarantee that genetic modifications will transfer to offspring, cloning is necessary to replicate these modifications.
In 2001, however, in response to observations that cloned animals are sometimes born sickly, deformed, and beset with neonatal diseases, the federal Food and Drug Administration (FDA) demanded a moratorium on the sale of food products derived from animal clones and their offspring until further research could be conducted. Scientists then determined that the majority of neonatal problems in clones arise from epigenetic, or environmental, factors. Because such problems are not DNA-based, cloned animals are unlikely to transfer them to their offspring. The FDA wisely lifted this moratorium in 2008, concluding that the risk of consuming products from cloned sources was no higher than that of consuming products from non-cloned sources. Furthermore, scientists discovered that deformities occur at similar rates when other alternative breeding techniques, such as embryo transfer and in-vitro fertilization, are employed.
Detractors of animal cloning point to the potential for unanticipated problems associated with the reduction of biodiversity in livestock breeding pools that results from the cloning process. A herd of clones bred from a single animal is highly vulnerable to contagious disease, because an animal's offspring tends to possess the same immunities as its progenitors, and a cloned animal has only one progenitor. Because the long-term environmental consequences of such practices have not been investigated, some argue that the FDA should reissue the moratorium. Moreover, many remain deeply uncomfortable with cloned meat; over 70% of consumers claim in surveys that they would not knowingly consume cloned animal meat.
The primary purpose of the passage is to
(A) argue against the use of cloning technology in commercial livestock production.
(B) define cloning and summarize recent technological developments in animal cloning.
(C) provide examples of medical problems that have the potential to be solved by livestock clone harvesting.
(D) explain why the FDA imposed a moratorium on the use of animal clones and their offspring in food production.
(E) discuss the advantages and disadvantages of animal clone harvesting and their impact on policy.
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Karthik
The source of the questions that i post from JUNE 2013 is from KNEWTON
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Karthik
The source of the questions that i post from JUNE 2013 is from KNEWTON
---If you find my post useful, click "Thank"
------Never stop until cracking GMAT---
