The primordial germ cells of Hemidactylium and other Amphibia.
The primordial germ cells of Hemidactylium and other Amphibia.
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DOI：
10.1002/jmor.1050410103
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发表时间：
1925-01-01
期刊：
影响因子：
--
通讯作者：
Humphrey, R. R.
中科院分区：
文献类型：
--
作者：
Humphrey, R. R.
The primordial germ cells of urodeles and anurans can occupy comparable positions in the embryo only in very early stages of development, if at all. When first recognizable as reproductive elements, their situation in the two amphibian orders is quite strikingly different.The germ cells first become recognizable in urodeles in the medial edge of the lateral mesoderm; there is no evidence that their position previous to this time is other than mesodermal. In the anura they are entodermal in association during early development; they are finally separated from the dorsal portion of the roof of the archenteron to form a single axial germ‐cell cord. No amphibian species studied showed a mode of origin different from that characteristic of its order.The so‐called migration of the amphibian germ cells to their definitive situation is interpreted as the result of growth shiftings of related parts. Germ cells do not migrate independently through the tissues. Aberrant or ectopic cells for the most part result from failures or faulty correlations of growth processes. Certain aberrant cells of the caudal portion of the body in urodeles indicate the inclusion of sex elements in the ventral as well as in the lateral mesoderm.
