这儿讨论的隐性遗传,只限于常染色体隐性遗传。这种遗传方式是由常染色体上的基因决定的,所以两个性别有同等机会受到影响。还有,因为是隐性遗传,所以要两个基因同是隐性时才显现出病症来。我们举一个苯丙酮尿症的例子来看。苯丙酮尿症的人不能形成苯丙氨酸羟化酶(phenylalanine 4-hydroxylase),不能把苯丙氨酸转变为酪氨酸,所以血液中和其它组织中苯丙氨酸积聚起来。过量的苯丙氨酸和它的衍生物——苯丙酮酸就在尿中排 The recessive gene discussed here is confined to autosomal recessive inheritance. This inheritance is determined by the genes on the autosome, so both genders have equal chances to be affected. Also, because it is recessive, so when the two genes are implicit, it shows symptoms. Let us give an example of phenylketonuria. People with phenylketonuria can not form phenylalanine 4-hydroxylase and can not convert phenylalanine into tyrosine, so that phenylalanine accumulates in the blood and in other tissues. Excess phenylalanine and its derivative, phenylpyruvate, are released in the urine