Generating knock-in parasites: Integration of an ornithine decarboxylase transgene into its chromosomal locus in Leishmania donovani

► A strategy to re-introduce targeted genes into the original chromosomal locus has been developed. ► A genomic fragment encompassing the ODC gene and lacking heterologous DNA sequences was utilized. ► This strategy offers a mechanism for stable complementation of a genetic lesion. ► Furthermore, no drug pressure is required to maintain the complemented gene.