Clone Farm

Factory farming could soon enter a new era of mass production. Companies in the US aredeveloping the technology needed to "clone" chickens on a massive scale. Once a chicken withdesirable traits has been bred or genetically engineered tens of thousands of eggs, which willhatch into identical copies, could roll off the production lines every hour. Billions of clonescould be produced each year to supply chicken farms with birds that all grow at the same rate,have the same amount of meat and taste the same.

This, at least, is the vision of the US's National Institute of Science and Technology,which has given Origen, Therapeutics of Burlingame, California, and Embrex of North CarolinaUSD 4. 7 million to help fund research. The prospect has alarmed animal welfare groups, whofear it could increase the suffering of farm birds.

That's unlikely to put off the poultry industry, however, which wants disease-resistant birds that grow faster on less food. "Producers would like the same meat quantity but to use reducedinputs to get there", says Mike Fitzgerald of Origen. To meet this demand, Origen aims to"create an animal that is effectively cloned", he says. Normal cloning doesn't work in birdsbecause eggs can't be removed and implanted. Instead, the company is trying to bulk-growembryonic stem cells taken from fertilized eggs as soon as they're laid. "The trick is to culturethe cells without them starting to distinguish, so they remain pluripotent", says Fitzgerald.

Using a long-established technique, these donor ceils will then be injected into the embryoof a freshly laid, fertilized recipient egg, forming a chick that is a "chimera". Strictly speakinga chimera isn't a clone, because it contains cells from both donor and recipient. But Fitzgeraldsays it will be enough, say, 95 percent of a chicken's body develops from donor cells. "In thepoultry world, it doesn't matter if it's not 100 percent," he says.

Another challenge for Origen is to scale up production. To do this, it has teamed up with"Embrex, which produces machines that can inject vaccines into up to 50, 000 eggs an hour.Embrex is now trying to modify the machines to locate the embryo and inject the cells intoprecisely the right spot without killing it.

In future, Origen imagines freezing stem cells from different strains of chicken. If orderscome in for a particular strain, millions of eggs could be produced in months or even weeks. Atpresent, maintaining all the varieties the market might call for is too expensive for breeders, andit takes years to breed enough chickens to produce the billions of eggs that farmers need.

Which statement is the best description of the new era of factory farming according to the first paragraph?

A.Eggs are all genetically engineered.

B.Thousands of eggs are produced every hour,

C.Cloned chickens are bulk-produced with the same growth rate, weight and taste.

D.Identical eggs can be hatched on the production lines.

42、 Which institution has offered USD 4. 7 million to fund the research?

A.The US's National Institute of Science and Technology.

B.Origen Therapeutics of Burlingame, California.

C.Embrex of North Carolina.

D.Animal welfare groups.

43、 In the third paragraph, by saying " Producers would like the same meat quantity but to use reduced inputs to get there" Mike Fitzgerald means that he wishes

A.chickens' quality could be maintained but with less investment

B.chickens' taste could be improved but at less costs

C.chickens' growth rate could be quickened but with less inputs

D.chickens could grow to the same weight but with less feed

44、 Which of the following statements about Origen and Embrex is correct according to the fifth paragraph?

A.Origen and Embrex will jointly invent machines to increase production.

B.Origen wants to purchase an efficient donor cell-injecting machine.

C.Origen has joined hands with Embrex in producing cell-injecting machines.

D.Origen is the leading company in producing embryo-locating machines.

45、 The technology of freezing stem cells from different strains of chicken can do all the following EXCEPT that

A.farmers can order certain strains of chicken only

B.Origen can supply all the strains of chicken the market might need

C.chicken farmers order certain strains of chicken for economic reasons

D.chicken farmers can be supplied with whatever they need

參考答案：

DDABA   DBCCA   CADCA

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