Early Events in Frog Blastomere Fate Determination

摘要: Publisher Summary Xenopus embryos are amenable to experimental perturbation throughout all stages of development. Many tests fate specification, determination, and commitment possible. In Xenopus, there is the added advantage that naturally fertilized eggs often cleave in predictable, stereotypic patterns, three cardinal axes can be recognized by first cleavage. The animal–vegetal axis, which will transformed into anterior–posterior axis at gastrulation, identified unfertilized asymmetric distribution pigment granules animal hemisphere. dorsal–ventral shortly after fertilization a change hemisphere pigmentation caused cytoplasmic reorganizations response entry sperm. Finally, cleavage furrow defines midsagittal plane eggs, identifying left right sides. These characteristics make it possible identify specific lineages just as has been done invertebrates with invariant patterns. This chapter explores rearrangements positioning maternal factors may involved specifying dorsal during early stages. It also demonstrates position blastomere critical for establishing whether its descendants contribute retina, initial steps pathway retinal cell specification.