Determination of anterior endoderm in Xenopus embryos.

Grafts of anterior endoderm from embryos at stage 28 or later developed according to their fate (i.e., anterior) when transplanted posteriorly. Conversely, grafts from earlier embryos developed according to their new location (i.e., posterior). However, endoderm grafted along with its mesodermal and ectodermal sheath retained its fate regardless of the stage of the donor. We conclude that anterior endoderm in Xenopus embryos is determined at about stage 25 under the influence of mesoderm. Dev Dyn 2000;218:531–536. © 2000 Wiley-Liss, Inc.