title: Reply.
authors.affiliation: Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Roger G
authors.initials: RG
authors.lastname: Whittaker
authors.affiliation: Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Grainne
authors.initials: G
authors.lastname: Gorman
authors.affiliation: Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ng
authors.affiliation: Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Douglass M
authors.initials: DM
authors.lastname: Turnbull