送交者: Latino2 于 October 25, 2004 19:01:09:
回答: A few more questions 由 吴礼 于 October 25, 2004 16:30:03:
1. 用遗传工程的手段把老鼠的１６号号染色体加成三体。结果耗子表现出类似人蒙古症的表型。
Partial copy may or may not cause the same effect, depends on which "segment" of the chromosome is triplicated. This is exactly how the researchers worked. They moved segment by segment, untill they narrowed it down to a specific region which only contain about 20 genes. They were very excited in the begining. However, triplication of these genes didn't resulted Down's phenotype, as shown in this report.
This is a big blow to the Down's research community. They have to consider a system approach now.
2. No, it doesn't work in reverse way.
3. No, this research has nothing to do with diaglostical application of Down's syndrome. Identifiy abnormal chormosome is still the standard way. This research is to understand why an extra copy of the 21th chromosome will cause the syndrome.