Structural Variations Affecting Genes and Transposable Elements of Chromosome 3B in Wheats

Area of Science:

• Genomics
• Plant Science
• Evolutionary Biology

Background:

• Structural variations (SVs) like copy number and presence-absence variations influence genome composition and phenotypes.
• Studying SVs in wheat was historically challenging due to the lack of a reference genome sequence.
• Recent advancements in wheat genomic resources have enabled comprehensive SV investigations.

Purpose of the Study:

• To assess the extent of structural variations affecting genes and transposable elements (TEs) in a Triticeae diversity panel.
• To investigate intraspecific and interspecific genomic variability in cultivated and wild wheat accessions.
• To explore the impact of SVs on genome composition and potential phylogenetic relationships.

Main Methods:

• High-coverage shotgun sequencing of sorted chromosome 3B DNA from 45 Triticeae accessions.
• Application of dedicated bioinformatics approaches for SV detection.
• Analysis of genes and transposable elements (TEs) for variability assessment.

Main Results:

• 23% of genes exhibited variability within the analyzed panel.
• 330 genes were identified as absent in the reference accession (Chinese Spring).
• 60% of TE-derived markers were absent in at least one accession, indicating high TE variability.
• Chromosome extremities showed the highest concentration of observed variability.

Conclusions:

• The study provides deep insights into genomic variability within complex Triticeae genomes at both intraspecific and interspecific levels.
• High levels of variability in genes and TEs were observed across diverse wheat species.
• Findings suggest a phylogeny shaped by independent hybridization events leading to different hexaploid species.