F Siamois is considered a candidate gene involved in differentiation of the Nieuwkoop Center on the ventral side of the early Xenopus embryo. F Alternative splicing of pre mRNAs does not lead to differences in the function of the resulting mature mRNAs, since during splicing the introns are removed. T Roundabout is an important protein involved in axon guidance, because it helps regulate the crossing of neurons over the ventral midline of embryos. The midblastula transition in Xenopus would occur earlier in an embryo derived from an oocyte to which a large excess of cytoplasm had been added. F Experiments involving guidepost neurons in grasshoppers are important because they suggest that growth cones respond to long-range diffusible signals.
Germ plasm is a common feature within animal embryos.
Answer the following questions about the nature and formation of this material. Oskar is a maternal effect gene required for formation of germ plasm in Drosophila . PIE-1 protein is thought to be important for the differentiation of the cells that form the germ line in C. elegans. PIE-1 is thought to repress transcription in germ line precursors. Since she is a heterozygote, the offspring will be normal.