Gardiner D M, Hoppe D M
Developmental Biology Center, University of California Irvine 92697, USA.
J Exp Zool. 1999 Jul 1;284(2):207-16. doi: 10.1002/(sici)1097-010x(19990701)284:2<207::aid-jez10>3.3.co;2-2.
In recent years, there has been an increase in the incidence of frog deformities throughout many of the northern states of North America. The most readily noticed malformations involve the hindlimbs of peri-metamorphic animals. We have analyzed skeletal preparations of metamorphosing mink frogs (Rana septentrionalis) collected from a site in Minnesota, in order to develop a better understanding of the possible causes. In this paper we describe the categories of abnormalities found at this site. The spectrum of deformities includes missing limbs, truncated limbs, extra limbs (including extra pelvic girdles), and skin webbings. We also describe a newly recognized malformation of the proximal-distal limb axis, a bony triangle. In this abnormality, the proximal and distal ends of the bone are adjacent to one another forming the base of a triangle. The shaft of the bone is bent double and protrudes laterally, the midpoint of the bone forming the apex of the triangle. In this paper we consider several recently proposed explanations for the recent outbreak of amphibian deformities. Based on our analysis, we conclude that the spectrum of abnormalities seen in these frogs is remarkably similar to the range of abnormalities that has been reported as a result of exposure of developing vertebrates to exogenous retinoids. Given the potential implications of this possibility for the welfare of humans as well as wildlife, further studies are needed to determine whether environmental retinoids are responsible for the frog deformities at the site we have examined.
近年来，在北美洲许多北部州，青蛙畸形的发生率有所上升。最容易被注意到的畸形涉及变态发育阶段动物的后肢。我们分析了从明尼苏达州一个地点收集的正在变态的北美貂蛙（Rana septentrionalis）的骨骼标本，以便更好地了解可能的原因。在本文中，我们描述了在该地点发现的异常类别。畸形谱包括肢体缺失、肢体截断、额外肢体（包括额外的骨盆带）和皮肤蹼。我们还描述了一种新发现的近端 - 远端肢体轴畸形，即骨三角形。在这种异常中，骨头的近端和远端彼此相邻，形成三角形的底边。骨头的骨干弯曲成两段并向侧面突出，骨头的中点形成三角形的顶点。在本文中，我们考虑了最近提出的几种对两栖动物畸形近期爆发的解释。基于我们的分析，我们得出结论，这些青蛙中看到的异常谱与已报道的发育中的脊椎动物接触外源性视黄酸所导致的异常范围非常相似。鉴于这种可能性对人类以及野生动物福利的潜在影响，需要进一步研究以确定环境视黄酸是否是我们所研究地点青蛙畸形的原因。
