Exploring the Diverse Genetic Roots of Wild Rye Grasses

Jenn Hoskins
16th April, 2024

Exploring the Diverse Genetic Roots of Wild Rye Grasses

Image Source: Natural Science News, 2024

Key Findings

  • Study conducted by the Swedish University of Agricultural Sciences on the Elymus s.s. plant genus
  • Elymus s.s. is divided into two main groups: American species in one and Eurasian species in another, suggesting different evolutionary origins
  • Within these groups, further subdivisions indicate complex migration and evolution patterns among the species
Understanding the genetic relationships and origins of plant species is crucial for biodiversity conservation and agricultural improvement. One such group under the microscope is the Elymus genus, which belongs to the Triticeae tribe and is closely related to vital cereals and forage grasses. Elymus sensu stricto (s.s.), in particular, includes tetraploid species with a genome derived from two ancestral grasses: Hordeum and Pseudoroegneria. This genetic combination is referred to as the StH genome. The study of Elymus s.s. has been complicated by its vast species diversity, widespread distribution, and morphological variability. Additionally, species within this genus have shown a tendency to interbreed and may have multiple origins, making it difficult to trace their evolutionary history. However, a recent study by the Swedish University of Agricultural Sciences has shed light on these complex relationships[1]. Utilizing advanced genetic techniques, researchers analyzed genome-wide DArTseqLD data from 57 taxa within the Elymus s.s. group and related species. DArTseqLD is a method that captures and sequences thousands of DNA fragments across the genome, providing a comprehensive picture of the genetic makeup of these plants. The analyses employed included SplitsTree, STRUCTURE, and principal component analysis (PCoA). SplitsTree is a method for constructing phylogenetic networks that can capture more complex evolutionary relationships than traditional tree models. STRUCTURE is a software package that uses genetic data to identify distinct populations or genetic clusters within a species. PCoA is a statistical tool that helps to visualize genetic variation and relationships among individuals or species. The results from these analyses were striking. They revealed that Elymus s.s. is divided into two major clades, or groups, that are highly correlated with their geographical origins. American species formed one clade, while Eurasian species formed another, suggesting that Elymus s.s. likely has at least two independent origins. This finding aligns with previous research that indicated multiple origins for American and Eurasian species[2]. The Eurasian and American clades were further subdivided into three and two subclades, respectively. This subdivision suggests a complex pattern of migration and evolution within the Elymus s.s. group. The data indicated that there have been multiple migrations of Elymus species between North and South America and between America and Eurasia. Earlier studies had attempted to unravel the genetic history of Elymus species using different methods. For instance, research had previously used nuclear and chloroplast DNA to propose that the St genome from Pseudoroegneria was the maternal ancestor for Elymus s. l. polyploids[3]. Moreover, variation in repeated nucleotide sequences (RNSs) was employed to investigate the genome constitution of South American Elymus, providing insights into the presence of the H genome from Hordeum in these species[4]. The current study builds upon these findings, using genome-wide data to provide a more detailed understanding of the genetic structure and evolutionary history of the genus. The implications of this study are significant for the classification of Elymus s.s. The genetic insights gained could lead to a reclassification of the genus, with sections based on phylogenetic relationships rather than solely on morphology or geography. Such a reclassification would be invaluable for both scientific understanding and practical applications in crop breeding, as it would reflect the true evolutionary relationships within this important group of plants. In conclusion, the research from the Swedish University of Agricultural Sciences has provided a clearer picture of the genetic structure and origins of Elymus s.s. By incorporating genome-wide data and sophisticated analytical methods, the study has highlighted the complex evolutionary history of this genus, with implications for its classification and use in agriculture. This work not only ties together previous findings but also expands our knowledge, offering a new perspective on the genetic diversity within the Triticeae tribe.

GeneticsPlant ScienceEvolution

References

Main Study

1) Genetic structure analyses reveal multiple origins of Elymus sensu stricto (Poaceae)

Published 15th April, 2024

https://doi.org/10.1007/s10722-024-01944-1

Related Studies

2) Diversity within the genus Elymus (Poaceae: Triticeae) as investigated by the analysis of the nr5S rDNA variation in species with St and H haplomes.

https://doi.org/10.1007/s00438-014-0907-4

3) Phylogeny and differentiation of the St genome in Elymus L. sensu lato (Triticeae; Poaceae) based on one nuclear DNA and two chloroplast genes.

https://doi.org/10.1186/s12870-015-0517-2

4) Genome analysis of South American Elymus (Triticeae) and Leymus (Triticeae) species based on variation in repeated nucleotide sequences.

Journal: Genome, Issue: Vol 40, Issue 4, Aug 1997


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