Zebrafish Embryos (IMAGE) Weizmann Institute of Science Caption Zebrafish embryos with fluorescent blood vessels helped solve the mystery regarding the origin of the lymphatic system. Credit Weizmann Institute of Science Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.