Reconstructed KIT-ligand proteins from CrocERV29 and a simplified diagram of the provirus. Maximum Likelihood phylogenies and sequence alignments were created from the reconstructed KIT-ligand proteins encoded by one lineage within CrocERV29. ERV IDs are provided within the tree and the alignment (see also Additional file 7). Four letter sequence names indicate the crocodilian species (‘Amis’ , A. mississippiensis; ‘Asin’ , A. sinensis; ‘Cpor’ , C. porosus; ‘Ggan’ , G. gangeticus). Shaded columns indicate the positions of indels within the alignment. Numbers within the tree indicate statistical support for the branches and the scale bars indicate branch length. Proviral structure is not to scale.