Genomic Diversity and Cytogenetics in Avena Species

The genus Avena exhibits remarkable genomic diversity, spanning diploid, tetraploid, hexaploid and even octoploid species. Its cultivated form, Avena sativa, is an allohexaploid composed of A, C and D subgenomes. Genome assemblies have revealed a mosaic structure shaped by successive polyploidisation events, large‐scale reorganisations and intergenomic translocations. Cytogenetic approaches, notably fluorescence in situ hybridisation (FISH) with repetitive DNA probes, have refined chromosome identification and clarified subgenome origins. High‐density genotyping‐by‐sequencing has delineated ancestral genome donors and traced chromosome rearrangements across species. This integrated cytogenomic framework underpins understanding of key agronomic traits—such as stress resistance, nutritional quality and water‐use efficiency—and informs breeding strategies that exploit wild germplasm and interspecific hybrids to enhance oat improvement globally.

Research from Nature Portfolio

Building on a high-quality reference assembly of Avena sativa and its diploid and tetraploid progenitors, recent work has mapped the mosaic architecture of the hexaploid genome, traced polyploidisation history and identified genome barriers that affect interspecific gene flow. Detailed analyses of gene families linked to human health and mapping-by-sequencing of water-use efficiency traits demonstrate the power of a comprehensive reference to accelerate genomics-assisted breeding. Comparative linkage mapping across diploid, tetraploid and hexaploid oats using genotyping-by-sequencing markers has illuminated extensive chromosome rearrangements, confirmed subgenome homologies and pinpointed inter‐ and intra‐genomic translocations that shaped modern genomes. Organellar genome sequencing in 25 Avena taxa has resolved maternal lineages of cultivated hexaploids, dating divergence events and identifying specific diploid and tetraploid donors, with direct implications for germplasm conservation and targeted hybridisation efforts.

Genomic Diversity and Cytogenetics in Avena Species publication trend

The graph below shows the total number of articles in genomic diversity and cytogenetics in avena species across all publications each year (not limited to Nature Index journals).

Technical terms

Allohexaploid: An organism with six sets of chromosomes derived from three distinct ancestral genomes.

Subgenome: One of the constituent ancestral genomes within a polyploid nucleus.

Fluorescence in situ hybridisation (FISH): A cytogenetic technique that uses fluorescent probes to visualise specific DNA sequences on chromosomes.

Polyploidisation: The process by which an organism acquires one or more additional complete sets of chromosomes.

References

1. Genome Variability in Artificial Allopolyploid Hybrids of Avena sativa L. and Avena macrostachya Balansa ex Coss. et Durieu Based on Marker Sequences of Satellite DNA and the ITS1–5.8S rDNA Region. International Journal of Molecular Sciences (2024).
2. The mosaic oat genome gives insights into a uniquely healthy cereal crop. Nature (2022).
3. High-density marker profiling confirms ancestral genomes of Avena species and identifies D-genome chromosomes of hexaploid oat. Theoretical and Applied Genetics (2016).
4. Oat evolution revealed in the maternal lineages of 25 Avena species. Scientific Reports (2018).
5. Comparative linkage mapping of diploid, tetraploid, and hexaploid Avena species suggests extensive chromosome rearrangement in ancestral diploids. Scientific Reports (2019).
6. A universal karyotypic system for hexaploid and diploid Avena species brings oat cytogenetics into the genomics era. BMC Plant Biology (2021).
7. New evidence confirming the CD genomic constitutions of the tetraploid Avena species in the section Pachycarpa Baum. PLOS ONE (2021).