|
阅读理解： Clone Farm Factory farming could soon enter a new era of mass production. Companies in the US are developing the technology needed to clone chickens on a massive scale. Once a chicken with desirable traits has been bred or genetically engineered, tens of thousands of eggs, which will hatch into identical copies, could roll off the production lines every hour. Billions of clones could 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. Thats 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 reduced inputs to get there, says Mike Fitzgerald of Origen. To meet this demand, Origen aims to create an animal that is effectively a clone, he says. Normal cloning doesnt work in birds because eggs cant be removed and implanted, Instead, the company is trying to bulk-grow embryonic stem cells taken from fertilized eggs as soon as theyre laid. The trick is to culture the cells without them starting to distinguish, so they remain pluripotent, says Fitzgerald. 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 into precisely the right spot without killing it. | 
