And just as it usually takes several individuals to cause an incident, so it often takes several genetic variations, plus ambient factors, to cause a disease. Genes often work together, sometimes aided by factors such as a person’s diet or behavior, to cause a condition.
另一方面，我们已经开始理解某些词汇——也就是看似与过往某些事件相关的特定的遗传变异。具体到基因领域，这些事件代表的是疾病和健康问题。正如通常需要几种因素共同作用才会造成事故一样，同样也需要若干种遗传变异，再加上周围环境因素的共同作用，才会诱发某种疾病。基因常常共同作用，有时在个人饮食或行为因素的辅助下，才会导致健康问题。