Pegasides name of a nymph who had sex with the Trojan prince Emathion and gave birth beside the river Granicus to Atymnius. The latter was eventually killed by Odysseus in the Trojan War. Pegasides Pegasides () were nymphs of Greek mythology connected with wells and springs, specifically those that the mythical horse Pegasus created by striking the ground with his hooves. According to Greek mythological tradition the winged horse Pegasus was the son of Poseidon, sea and river god of the Greeks, equivalent to the Roman Neptune. The hero Bellerophon needed the untamed Pegasus to help him defeat the monster Chimera.
Chimera (genetics) give rise to the embryo proper. Embryos that are to be used in chimeras can further be genetically altered in order to specifically contribute to only one part of chimera. An example is the chimera built off of ES cells and tetraploid embryos, which are artificially made by electrofusion of two two-cell diploid embryos. The tetraploid embryo will exclusively give rise to the trophectoderm and primitive endoderm in the chimera. There are a variety of combinations that can give rise to a successful chimera mouse and — according to the goal of the experiment — an appropriate cell and embryo