Correspondence on Lovell et al.: response to Bornelöv et al.

While the analysis of Bornelöv et al. is informative, they provide evidence for the existence of only 3% of the reported avian missing genes set, and thus do not significantly challenge our main findings that specific groups of syntenic protein-coding genes are missing in birds.This is a response to the Correspondence article: https://www.dx.doi.org/10.1186/s13059-017-1231-1.