Demographic history and divergence of sibling grouse species inferred from whole genome sequencing reveal past effects of climate change

Ying-Xin Jiang,Peter Halvarsson,Kai Song,Yue-Hua Sun,Bin Gao,Jon E Swenson,Yun Fang,Jacob Höglund,Siegfried Klaus

doi:10.1186/s12862-021-01921-7

Abstract

BackgroundThe boreal forest is one of the largest biomes on earth, supporting thousands of species. The global climate fluctuations in the Quaternary, especially the ice ages, had a significant influence on the distribution of boreal forest, as well as the divergence and evolution of species inhabiting this biome. To understand the possible effects of on-going and future climate change it would be useful to reconstruct past population size changes and relate such to climatic events in the past. We sequenced the genomes of 32 individuals from two forest inhabiting bird species, Hazel Grouse (Tetrastes bonasia) and Chinese Grouse (T. sewerzowi) and three representatives of two outgroup species from Europe and China.ResultsWe estimated the divergence time of Chinese Grouse and Hazel Grouse to 1.76 (0.46–3.37) MYA. The demographic history of different populations in these two sibling species was reconstructed, and showed that peaks and bottlenecks of effective population size occurred at different times for the two species. The northern Qilian population of Chinese Grouse became separated from the rest of the species residing in the south approximately 250,000 years ago and have since then showed consistently lower effective population size than the southern population. The Chinese Hazel Grouse population had a higher effective population size at the peak of the Last Glacial Period (approx. 300,000 years ago) than the European population. Both species have decreased recently and now have low effective population sizes.ConclusionsCombined with the uplift history and reconstructed climate change during the Quaternary, our results support that cold-adapted grouse species diverged in response to changes in the distribution of palaeo-boreal forest and the formation of the Loess Plateau. The combined effects of climate change and an increased human pressure impose major threats to the survival and conservation of both species.

Highlights

The boreal forest is one of the largest biomes on earth, supporting thousands of species
The demographic history of a species can be examined through reconstruction of the effective population size, using the information embedded in the genome sequences of a diploid species [1]
Phylogenetic relationships The trees based on the three different methods (Bayesian, Maximum Likelihood and Neighbor Joining) used to infer the phylogenetic relationships largely concur and only show minor differences among the different populations of Hazel Grouse

Summary

Introduction

The boreal forest is one of the largest biomes on earth, supporting thousands of species. The global climate fluctuations in the Quaternary, especially the ice ages, had a significant influence on the distribution of boreal forest, as well as the divergence and evolution of species inhabiting this biome. We use whole genome sequences obtained from individuals belonging to a pair of boreal forest dwelling sibling grouse species: the Chinese Grouse Tetrastes sewerzowi and Hazel Grouse T. bonasia to infer their demographic histories and relate the inferred changes to known past climatic geological events and their climatic impacts [4]. Most of the boreal forest is found throughout the high northern latitudes from about 50°N to 70°N, but boreal forest occurs in mountain regions further to the south, such as at the southeastern edge of the Qinghai–Tibet Plateau (QTP) These forest areas used to be connected to the more widely distributed boreal forest to the north, but retracted to present distributions during the uplifting of the plateau [8]. It is argued that the evolution of present-day animals in the Arctic region is intimately connected to ancestors that first became adapted for life in cold regions in the high-altitude environments of the QTP (2.6 to 5 Mya), and were pre-adapted to cold climates during the ice age (2.6 to 0.1 Mya) [14,15,16]

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Results

Discussion

Conclusion