Letters to Nature

Nature 425, 175-178 (11 September 2003) | doi:10.1038/nature01838; Received 14 March 2003; Accepted 3 June 2003

Nuclear DNA sequences detect species limits in ancient moa

L. Huynen1, C. D. Millar2, R. P. Scofield3 & D. M. Lambert1

  1. Allan Wilson Centre for Molecular Ecology and Evolution, Institute of Molecular BioSciences, Massey University, Private Bag 102 904, Auckland, New Zealand
  2. Allan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
  3. Canterbury Museum, Rolleston Avenue, Christchurch 8001, New Zealand

Correspondence to: D. M. Lambert1 Email: D.M.Lambert@massey.ac.nz

Ancient DNA studies have typically used multi-copy mitochondrial DNA sequences1, 2. This is largely because single-locus nuclear genes have been difficult to recover from sub-fossil material3, restricting the scope of ancient DNA research. Here, we have isolated single-locus nuclear DNA markers to assign the sex of 115 extinct moa and, in combination with a mitochondrial DNA phylogeny, tested competing hypotheses about the specific status of moa taxa. Moa were large ratite birds that showed extreme size variation both within and among species4. For some taxa, this large variation was hypothesized to represent sexual dimorphism, while for others it was argued to reflect the existence of different species5. Our results show that moa were characterized by extreme reverse sexual dimorphism and as a result we have been able to clarify the number of moa species. For example, we show that the three recognized 'species' of Dinornis comprised only two monophyletic groups and that two of these 'species' comprised individuals of one sex only. This study also illustrates that single-locus nuclear DNA sequences can be consistently recovered from ancient material.