Valparaiso University 1 article published in JoVE Neuroscience Loss-of-Function Approach in the Embryonic Chick Retina by Using Tol2 Transposon-Mediated Transgenic Expression of Artificial microRNAs Chizu Makino Nakamoto1, Masaru Nakamoto1 1Department of Biology, Valparaiso University We have developed a novel loss-of-function approach that involves the introduction and genomic integration of artificial micro-RNA sequences into chick embryos by using in ovo electroporation and the Tol2 transposon system. This technique provides a robust and stable gene knockdown methodology for studies of gene function during development.