Huntington舞蹈症:一组研究者系统研究了一个患有此病的委内瑞拉大家系。Gusella等人用随机方法,发现由同一限制性内切酶所产生的两个不同的RFLP在北美家系和委内瑞拉大家族中都与Hunt1ngton舞蹈症有关。他们用G8探针检测时,将这个多态系统定位在4号染色体上。目前他们正试图用“染色体移步法”分离出引起Huntiongon舞蹈症的基因。 Huntington Chorea: A group of researchers systematically studied a large Venezuelan family with this disease. Gusella et al. Used randomized methods to find that two different RFLPs produced by the same restriction endonuclease were associated with Hunt1ngton’s disease in both North American and Venezuelan families. When they tested with the G8 probe, they mapped the polymorphic system on chromosome 4. At present, they are trying to use the “chromosome shift method” to isolate Huntiongon cholera-causing genes.