Phallus development in the turtle Trachemys scripta.
Phallus development in the turtle Trachemys scripta.
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Trachemys scripta 龟的阴茎发育。
DOI：
10.1159/000363631
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Cohn,MartinJ
中科院分区：
文献类型：
--
作者：
Larkins,ChristineE;Cohn,MartinJ
Development of a phallus occurs in almost all amniotes; however, considerable variation in phallus morphology among different amniote lineages has contributed to the debate about their structural homology. Mammals are the only amniotes that form a closed urethral tube within the penis. In contrast, the phallus of reptiles and birds has an open urethral groove, or sulcus spermaticus, that facilitates directional flow of sperm along the penis. One condition of structural homology is that the organs should share a common developmental origin; de novo development from different embryonic progenitors would indicate that the structure re-evolved in a new position. Although a common developmental origin does not itself demonstrate homology, different origins could indicate a lack of homology. To further understand how development of external genitalia evolved in amniotes, we examined this in the turtle Trachemys scripta. We found that phallus development in the turtle closely resembles that of mice at the tissue, cellular, and molecular levels, consistent with the hypothesis that their phalluses are homologous structures. We find that acquisition of specialized characters, such as a closed urethral tube, involved lineage-specific specialization of the common plan for amniote phallus development.
