North-south divergence within Godlewski’s Bunting coincides with the uplift of the Tibetan Plateau

Genetic study uncovers deep genetic divergence within the Godlewski’s Bunting.

A few weeks ago, I wrote about the genetic structure in some corvid species (see here). Several species, such as the Rook (Corvus frugilegus), the Jackdaw (Corvus monedula and Corvus dauuricus) and the Eurasian Magpie (Pica pica), show a striking divergence between eastern and western populations. A recent study in the journal BMC Evolutionary Biology reports a similar pattern in the Godlewski’s Bunting (Emberiza godlewskii) with one important difference: the divergence is orientated north-south.

Godlewski's_Bunting.jpg

Godlewski’s Bunting © Jargal Lamjav | Wikimedia Commons

 

Five Genetic Markers

On the bushy slopes of China, you can sometimes catch a glimpse of the Godlewski’s Bunting. Although this small passerine is widely distributed in central China, little is known about its genetic structure and evolutionary history. That is why, Jiande Li and colleagues collected 190 samples across the range of this species. They sequenced three mitochondrial genes and two nuclear introns. The analyses of these markers revealed a deep divergence between two lineages.

The genetic split was dated to about 3.26 million years ago, which coincides with the uplift of the Qinghai-Tibet Plateau (QTP). This vast plateau probably divided the Godlewski’s Bunting into a northern and southern population. A similar pattern has been observed in the Tibetan Partridge (Perdix hodgsoniae).

bunting.png

Genetic analyses reveal a deep divergence within the Godlewski’s Bunting. From: Li et al. (2019) BMC Evolutionary Biology

 

Expansion

The authors did not find strong evidence for historical gene flow, suggesting that both populations went their separate ways after the initial split. Their independent evolutionary paths are nicely illustrated by the demographic analyses: the northern lineage exhibited an intensive expansion whereas the southern population showed a lower rate of population growth. These differences can be attributed to habitat availability during the late Pleistocene. Ecological niche modelling indicates that the northern population had a bigger area at its disposal compared to the southern population.

In summary, the deep divergence observed in the Godlewski’s Bunting can be explained by a series of geological events (mainly the uplift of the QTP) and subsequent environmental changes during the ice ages.

 

References

Li, J., Song, G., Liu, N., Chang, Y., & Bao, X. (2019). Deep south-north genetic divergence in Godlewski’s bunting (Emberiza godlewskii) related to uplift of the Qinghai-Tibet Plateau and habitat preferences. BMC Evolutionary Biology19(1), 161.

 

Further Reading on Deep Genetic Divergences

 

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