Mitochondrial sequences reveal a clear separation between Angolan and South African giraffe along a cryptic rift valley

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Date
2014Author
Bock, Friederike
Fennessy, Julian
Bidon, Tobias
Tutchings, Andy
Marais, Andri
Deacon, Francois
Janke, Axel
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Background: The current taxonomy of the African giraffe (Giraffa camelopardalis) is primarily based on pelage
pattern and geographic distribution, and nine subspecies are currently recognized. Although genetic studies have
been conducted, their resolution is low, mainly due to limited sampling. Detailed knowledge about the genetic
variation and phylogeography of the South African giraffe (G. c. giraffa) and the Angolan giraffe (G. c. angolensis) is
lacking. We investigate genetic variation among giraffe matrilines by increased sampling, with a focus on giraffe key
areas in southern Africa.
Results: The 1,562 nucleotides long mitochondrial DNA dataset (cytochrome b and partial control region)
comprises 138 parsimony informative sites among 161 giraffe individuals from eight populations. We additionally
included two okapis as an outgroup. The analyses of the maternally inherited sequences reveal a deep divergence
between northern and southern giraffe populations in Africa, and a general pattern of distinct matrilineal clades
corresponding to their geographic distribution. Divergence time estimates among giraffe populations place the
deepest splits at several hundred thousand years ago.
Conclusions: Our increased sampling in southern Africa suggests that the distribution ranges of the Angolan and
South African giraffe need to be redefined. Knowledge about the phylogeography and genetic variation of these
two maternal lineages is crucial for the development of appropriate management strategies.