It's impossible to say how much a person's behaviour is predetermined by their genes.很难说一个人的行为有多少是由遗传基因预先决定的。Sufferers are more likely to be genetically predisposed.患者更可能在遗传基因上有患病倾向。He believes that one's personality is determined mostly by genetics.他认为人的性格主要取决于遗传基因。Eye colour is genetically determined.眼睛的颜色是由遗传基因决定的。