Mitochondrial DNA variation of the common hippopotamus: evidence for a recent population expansion Okello, J. B. A. ; Nyakaana, S. ; Masembe, C. ; Siegismund, H. R. ; Arctander, P. Abstract Publication: Heredity Pub Date: September 2005 DOI: 10.1038/sj.hdy.6800711 Bibcode: 2005Hered..95..206O