The funding information was inadvertently omitted from the published online
version of the manuscript.

The Acknowledgements section should read:

This work was supported by a grant-in-aid from the Heart and Stroke foundation
of Ontario to JP (#T6748). GC was supported by a Research Training award from
the Hospital for Sick Children. The authors wish to thank Dr. James Wasmuth
and Tuan On for their assistance in compiling data for the phylogenetic
profiles.