Opitz J M
Am J Med Genet. 1985 May;21(1):1-11. doi: 10.1002/ajmg.1320210102.
Identical anomalies produced by such different causes as aneuploidy, gene mutation, teratogenic chemicals, and certain surgical procedures show that embryonic primordia respond as units in the production of anomalies of anatomical structure. Hence, they must also act as units during normal ontogeny. The presence of identical malformations in different mammalian species identifies developmental and anatomical homology by virtue of descent from a common ancestor. These dys- and orthomorphogenetically reactive units are the equivalents of the classical experimental embryologist's epimorphic fields, which are those units of the embryo in which the development of complex structures appropriate to the species is determined and controlled in a spatially coordinated, temporally synchronous, and epimorphically hierarchical manner that expresses both species-nonspecific (that is, phylogenetic) and species-specific genetically coded developmental information. Thus, there is some merit in taking a long view of development.
由非整倍体、基因突变、致畸化学物质和某些外科手术等不同原因产生的相同异常表明，胚胎原基在产生解剖结构异常时作为一个整体做出反应。因此，它们在正常个体发育过程中也必定作为一个整体发挥作用。不同哺乳动物物种中相同畸形的存在通过源自共同祖先而确定了发育和解剖学上的同源性。这些发育异常和正常形态发生反应性单位等同于经典实验胚胎学家的形态发生场，形态发生场是胚胎中的那些单位，在其中，适合该物种的复杂结构的发育以空间协调、时间同步且形态发生层次的方式被确定和控制，这种方式表达了物种非特异性（即系统发育）和物种特异性的遗传编码发育信息。因此，从长远角度看待发育是有一定价值的。
