Conservation and variability of long-range interactions in structurally diverse maize genomes

Area of Science:

• Genomics and Epigenetics
• Plant Molecular Biology
• Maize Genetics

Background:

• Chromatin interactions are crucial for gene regulation.
• Maize inbreds show genomic variation, while F1 hybrids exhibit hybrid vigor.
• Long-range genomic interactions in maize inbreds and hybrids remain understudied.

Purpose of the Study:

• To investigate long-range chromatin interactions in maize inbreds and their F1 hybrids.
• To correlate 3D genomic architecture with gene expression patterns, particularly non-additive expression in hybrids.

Main Methods:

• Performed H3K4me3/H3K27ac HiChIP in two maize inbred lines and their reciprocal F1 hybrids.
• Analyzed genotype-specific and shared chromatin interactions.
• Correlated interaction patterns with gene expression data.

Main Results:

• Identified distinct chromatin interactions specific to inbred or hybrid genotypes.
• Observed dominant or over-dominant expression for genes with hybrid-specific interactions.
• Discovered unexpected gain or loss of interactions in hybrids compared to parents, linked to altered gene regulation.
• Detected inter-allelic interactions in hybrids, suggesting somatic chromosome interactions.

Conclusions:

• 3D regulatory networks in maize hybrids offer a potential explanation for non-additive gene expression.
• Genomic structural variations and their impact on chromatin interactions contribute to hybrid vigor.