reSeArCH Letter
mammals and birds. This work is part of the PhD thesis of J.A.-L., supported
by the CONICYT Doctoral Fellowship 21130943. C.V. was supported by the
Leverhulme Trust (RPG-2013-185 and RPG-2017-071). C.E.H. and E.R.-S. were
supported by FONDECYT grants 1170815 and 1170486.
Author contributions J.A.-L., C.E.H., E.R.-S. and C.V. contributed to all aspects of
this work.
Competing interests The authors declare no competing interests.
Additional information
supplementary information is available for this paper at https://doi.org/
10.1038/s41586-019-1476-9.
Correspondence and requests for materials should be addressed to J.A. or C.V.
Peer review information Nature thanks Olaf Bininda-Emonds, Isabella Capellini
and the other, anonymous, reviewer(s) for their contribution to the peer review
of this work.
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reprints.