Five cloned piglets, genetically modified so that their organs are much less likely to be rejected by a human donor recipient, have been born in the US.
More than 62000 people in the US alone are waiting to receive donated hearts, lungs, livers, kidneys and pancreases. The number of human donors falls far short of demand. Pig organs are of a similar size to human organs, and some scientists hope they might be used to help meet the shortfall. But previous attempts to transplant unaltered pig tissue into humans have failed, due to immune rejection of the tissue.
The five piglets, born on Christmas Day, lack a gene for an enzyme that adds a sugar to the surface of pig ceils. The sugar would trigger a patient’s immune system into launching an immediate attack.
"This advance provides a near-time solution for overcoming the shortage of human organs for transplants, as well as insulin-producing cells to cure diabetes," says David Ayares, vice pres
A. To knock out one copy of the gene for the enzyme.
B. To study more genes in their program.
C. To test whether a virus from the pigs could infect human cells.
D. To transplant organs created from PPL pigs into patients
There have been several claims to have cloned humans over the past few years. Most have been bogus. But the announcement made this week by Woo Suk Hwang, of Seoul National University in South Korea, and his colleagues, is serious. It is the first to achieve the accolade of publication in a peer-reviewed scientific journal. Dr. Hwang s work appears in Science.
The terminology of human development has become slippery over the past few years, in the hands of both "life-begins-at-conception" propagandists who want to stop this sort of research, and publicity-seeking scientists who have claimed more than they have really achieved. What Dr. Hwang and his team have created is not what developmental biologists would normally refer to as an embryo. But it is a genuine scientific advance. South Korea’s researchers have taken egg cells from volunteer women, removed the nuclei from those cells (which contain only half of the genetic complement required to make a human
A. criticism
B. satire
C. suspicion
D. appreciation
我来回答:
