Pleistocene climatic fluctuations and divergence with gene flow drive
continent-wide diversification in an African bird
- Bridget Ogolowa,
- Alan Brelsford,
- Jon Fjeldså,
- Andrea Fulgione,
- Louis Hadjioannou,
- Elisa Henderson,
- Robert Moyle,
- Michaella Moysi,
- Emmanuel Nwankwo,
- Loïs Rancilhac,
- Thomas Smith,
- Bridgett vonHoldt,
- Alexander Kirschel
Andrea Fulgione
Max Planck Institute for Plant Breeding Research
Author ProfileAbstract
Diversification mechanisms in Sub-Saharan Africa have long attracted
research interest with varying support for either allopatric or
parapatric models of speciation. However, studies have seldom been
performed across the entire continent, a scale which could elucidate the
relative importance of allopatric and parapatric models of divergence.
To shed light on continental-scale patterns of African biogeography and
diversification, we investigated the historical demography of a bird
with a continent-wide distribution in Sub-Saharan Africa, the
Yellow-rumped Tinkerbird, Pogoniulus bilineatus. We sampled populations
from across the continent and using genomic data, assessed genetic
diversity, structure, and differentiation, reconstructed the phylogeny,
and performed alternative demographic model selection between
neighbouring clade pairs. We uncovered substantial genetic structure and
differentiation patterns which corroborated the phylogenetic topology.
Structure was chiefly influenced by the arid corridor, a postulated
biogeographical barrier in Sub-Saharan Africa. Moreover, peak genetic
diversities coincided with postulated refugial areas while demographic
reconstructions between genetic lineages supported allopatric models
consistent with the Pleistocene Forest Refuge hypothesis. However,
within lineages, divergence with gene flow was supported. Continent-wide
patterns of diversification involve an integration of both allopatric
and parapatric mechanisms, with a role for both periods of divergence in
isolation and across ecological gradients. Furthermore, our study
emphasises the importance of the arid corridor as a primary
biogeographical feature across which diversification occurs, yet one
that has hitherto received scant attention regarding its importance in
avian diversification in Sub-Saharan Africa.20 Sep 2024Submitted to Molecular Ecology 23 Sep 2024Submission Checks Completed
23 Sep 2024Assigned to Editor
23 Sep 2024Review(s) Completed, Editorial Evaluation Pending
28 Sep 2024Reviewer(s) Assigned