DcSto: carrot Stowaway-like elements are abundant, diverse, and polymorphic

Area of Science:

• Genomics
• Molecular Biology
• Plant Science

Background:

• Miniature inverted-repeat transposable elements (MITEs) are abundant in eukaryotic genomes.
• Stowaway-like MITEs are a distinct class of MITEs with conserved terminal inverted repeats.
• Understanding MITEs in crop genomes like carrot (Daucus carota) is crucial for genetic studies.

Purpose of the Study:

• To identify and characterize Stowaway-like MITE families in the carrot genome.
• To investigate the distribution, copy number, and potential regulatory roles of these elements.
• To assess the polymorphism and recent activity of MITE insertions in different carrot populations.

Main Methods:

• Bioinformatic analysis of the carrot genome to identify MITE sequences.
• Southern blot hybridization to estimate copy number and distribution.
• Comparative analysis of insertion sites across different carrot populations.
• Sequence analysis to identify regulatory motifs within MITEs.

Main Results:

• Nine families of Stowaway-like MITEs (DcSto1-DcSto9) were identified in the carrot genome.
• DcSto elements are AT-rich with conserved terminal inverted repeats (TIRs).
• DcSto1 elements have a high copy number (approx. 5,000 per diploid genome) and show clustered insertions in euchromatic regions.
• Insertion sites are highly polymorphic across Daucus carota populations, suggesting recent mobilization.
• DcSto elements contain putative promoters and regulatory motifs, with some insertions near carrot genes.

Conclusions:

• The carrot genome harbors diverse Stowaway-like MITE families.
• DcSto elements are actively mobilizing and exhibit non-random insertion patterns.
• DcSto MITEs may play a role in regulating gene expression in carrots due to their location and sequence features.