Understanding Genetic Differences and Population History of Two Spruce Species

Greg Howard
31st May, 2024

Understanding Genetic Differences and Population History of Two Spruce Species

Image Source: Natural Science News, 2024

Key Findings

  • The study focused on Picea meyeri and P. mongolica, two spruce species in China
  • P. mongolica is an independent species, despite its hybrid ancestry with P. meyeri and P. koraiensis
  • Gene flow between P. meyeri and P. mongolica has occurred multiple times, but local adaptation has driven their differentiation
The taxonomic classification of Picea meyeri and P. mongolica has long been a subject of debate among scientists. To shed light on their genetic relatedness and evolutionary history, researchers from the Chinese Academy of Forestry employed genotyping-by-sequencing (GBS) technology to acquire whole-genome single nucleotide polymorphism (SNP) markers[1]. These markers were then used to assess population structure, population dynamics, and adaptive differentiation of these species. The study revealed that although the ancestor of P. mongolica was a hybrid of P. meyeri and P. koraiensis, P. mongolica is an independent Picea species. Phylogenetic and population structural analyses at the genomic level indicated that P. mongolica is more closely related to P. meyeri than to P. koraiensis, consistent with their geographic distributions. This finding aligns with previous research indicating that geographic isolation can contribute significantly to species divergence[2]. Interestingly, the study identified up to eight instances of interspecific and intraspecific gene flow between P. meyeri and P. mongolica. This gene flow suggests that while these species are distinct, they have shared genetic material over time, which is not uncommon in plant species undergoing speciation[3]. However, despite this gene flow, local adaptation has driven differentiation between the two species. This phenomenon of local adaptation aligns with findings from other studies, which show that local plants often perform better than foreign plants in their native environments due to evolutionary adaptations[4]. The researchers also examined the population size dynamics of P. meyeri and P. mongolica. They found that the effective population sizes of both species have generally decreased over time. Using Maxent modeling, the study projected that their habitat areas initially decreased from the Last Glacial Maximum (LGM) to the present but have since increased. However, under future climate scenarios, especially high-emission scenarios, the habitat areas of both species are expected to decrease, putting P. mongolica at risk of extinction and highlighting the urgent need for conservation efforts. Genotype-environment association analysis identified 96,543 SNPs associated with environmental factors, mainly related to adaptations to moisture and temperature. This finding underscores the importance of ecological adaptation in shaping the genetic makeup of species, which is consistent with the role of natural selection in driving speciation[2][5]. Selective sweeps revealed that the selected genes among P. meyeri, P. mongolica, and P. koraiensis are primarily associated with flowering, fruit development, and stress resistance in vascular plants. This research not only enhances our understanding of Picea species classification but also provides a basis for future genetic improvement and species conservation efforts. By leveraging advanced genomic technologies, the study offers valuable insights into the evolutionary processes that shape biodiversity and underscores the critical importance of protecting vulnerable species in the face of climate change.

GeneticsPlant ScienceEvolution

References

Main Study

1) Adaptive divergence, historical population dynamics, and simulation of suitable distributions for Picea Meyeri and P. Mongolica at the whole-genome level

Published 30th May, 2024

https://doi.org/10.1186/s12870-024-05166-6

Related Studies

3) Species divergence with gene flow and hybrid speciation on the Qinghai-Tibet Plateau.

https://doi.org/10.1111/nph.17956

4) A meta-analysis of local adaptation in plants.

https://doi.org/10.1371/journal.pone.0004010

5) Indirect evolution of hybrid lethality due to linkage with selected locus in Mimulus guttatus.

https://doi.org/10.1371/journal.pbio.1001497


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