DNA studies uncover the history of feathergrass evolution

Greg Howard
5th October, 2025

DNA studies uncover the history of feathergrass evolution

Stipa × kyzylordensis, a newly discovered hybrid feathergrass from Kazakhstan that scientists confirmed is the natural offspring of two different parent species.

Image adapted from: Sinaga et al. / CC BY (Source)

Key Findings

  • In Kazakhstan’s steppe region, researchers studied unusual feathergrasses displaying intermediate traits
  • Genetic analysis confirmed a new grass species, named Stipa × kyzylordensis, is a direct hybrid between Stipa arabica and Stipa richteriana
  • Two distinct genetic groups exist within the Stipa richteriana population, both contributing to hybridisation events with other Stipa species
Grasses of the genus Stipa, commonly known as feathergrasses, are a diverse group particularly abundant in arid regions of Central Asia. Understanding how these grasses have diversified is a complex task, particularly when considering the potential for new species to arise through hybridisation – the interbreeding of different species.[1] Research from Jagiellonian University focused on resolving the origins of some unusual grass specimens found in the steppes of Kazakhstan, where multiple Stipa species grow in close proximity. These specimens displayed characteristics that didn't neatly fit into existing classifications, prompting the question of whether they represented new species or hybrids. The problem lies in accurately identifying species, especially in groups where morphological differences are subtle. Traditionally, species were defined based on physical characteristics, but this approach can be misleading when hybridisation occurs. Hybrids can exhibit traits intermediate between their parent species, making classification difficult. Modern genetic tools offer a way to overcome these challenges. The study centered on individuals collected from the Kyzylorda region of Kazakhstan, which appeared to be intermediate forms between Stipa arabica and Stipa richteriana. To determine their origin, researchers employed an integrative taxonomy approach. This means combining multiple lines of evidence, including detailed morphological analysis (examining physical characteristics) and the use of genetic markers called SNPs (Single Nucleotide Polymorphisms). SNPs are variations in single DNA building blocks, and can be used to assess the genetic relationships between individuals and species. The morphological analysis confirmed that the specimens had traits falling between those of S. arabica and S. richteriana. Crucially, analysis of the SNPs revealed that these individuals were indeed F1 hybrids – meaning they were the direct offspring of a cross between the two parent species. This was supported by phylogenetic tree analysis, which showed the hybrid specimens clustering separately from both parent species, but positioned between them. Further genetic structure analysis showed a clear separation of the hybrid group, with roughly equal genetic contribution from both S. arabica and S. richteriana. Interestingly, the study revealed further complexity within the S. richteriana population itself. FastStructure analysis identified two genetically distinct groups, or cryptic genotypes, within this species. These different genotypes were also found to be involved in hybridisation events, contributing to the formation of other previously suspected hybrid species, namely S. × heptapotamica, S. × czerepanovii, and S. × korshinskyi. Based on this evidence, the researchers formally described a new nothospecies, S. × kyzylordensis, confirming its status as an F1 hybrid between S. arabica and S. richteriana. A nothospecies is a hybrid that is consistently recognised and reproductively isolated, but its parentage is known. This represents the first documented case of hybridisation between these two Stipa species, and provides molecular confirmation for the hybrid origin of several other species found in the Kazakh steppe. These findings build upon earlier work highlighting the importance of hybridisation in the evolution of grasses[2]. The study[2] showed that hybridisation is a common mechanism of speciation in the grass family, particularly at the edges of species’ distributions. The research in Kazakhstan demonstrates that this process is also occurring in more genetically distant species than previously thought. Furthermore, it underscores the importance of using integrative taxonomy to accurately identify species and understand their evolutionary relationships. The convergence of leaf shape toward different optima depending on habitat, as found in other grasses[3], may play a role in reproductive isolation and thus hybridisation, although this wasn’t directly investigated in the current study. The discovery of a rare intergeneric hybrid with strong parental dominance in inheritance patterns[4] also highlights the complexities of plant reproduction and the potential for unexpected genetic combinations, although this example is between different genera and not within Stipa. The current study provides a detailed example of how hybridisation can contribute to species diversity in a challenging environment, and emphasizes the need for continued research to fully understand the evolutionary processes shaping the Stipa genus.

GeneticsPlant ScienceEvolution

References

Main Study

1) Integrated genomics and morphological approach reveals interspecific gene flow cases and decodes the origin of selected feathergrasses (Poaceae, Stipa)

Published 1st October, 2025

https://doi.org/10.1038/s41598-025-08934-y

Related Studies

2) Morphological and genome-wide evidence for natural hybridisation within the genus Stipa (Poaceae).

https://doi.org/10.1038/s41598-020-70582-1

3) Leaf shape and size track habitat transitions across forest-grassland boundaries in the grass family (Poaceae).

https://doi.org/10.1111/evo.13722

4) New intergeneric orchid hybrid found in Romania × Pseudorhiza nieschalkii (Senghas) P.F.Hunt nothosubsp. siculorum H.Kertész & N.Anghelescu, 2020.

https://doi.org/10.1371/journal.pone.0241733


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