This study finds an asymmetrically induced enhancer upstream of the chick Lefty2 gene. The manuscript is technically sound, the text is organized, and the data is presented very well. Authors have acknowledged the limitations of using a reporter gene, however, the abstract and the body of the manuscript should be changed to reflect this. Notably, authors should avoid concluding a direct regulation of Lefty2 by Nodal, as their data does not make this connection. Overall, this is an important study that can lead to new research questions in fututere.