Combined analysis of transposable elements and structural variation in maize genomes reveals genome contraction outpaces expansion

by Manisha Munasinghe, Andrew Read, Michelle C. Stitzer, Baoxing Song, Claire C. Menard, Kristy Yubo Ma, Yaniv Brandvain, Candice N. Hirsch, Nathan Springer

Structural differences between genomes are a major source of genetic variation that contributes to phenotypic differences. Transposable elements, mobile genetic sequences capable of increasing their copy number and propagating themselves within genomes, can generate structural variation. However, their repetitive nature makes it difficult to characterize fine-scale differences in their presence at specific positions, limiting our understanding of their impact on genome variation. Domesticated maize is a particularly good system for exploring the impact of transposable element proliferation as over 70% of the genome is annotated as transposable elements. High-quality transposable element annotations were recently generated forde novo genome assemblies of 26 diverse inbred maize lines. We generated base-pair resolved pairwise alignments between the B73 maize reference genome and the remaining 25 inbred maize line assemblies. From this data, we classified transposable elements as either shared or polymorphic in a given pairwise comparison. Our analysis uncovered substantial structural variation between lines, representing both simple and complex connections between TEs and structural variants. Putative insertions in SNP depleted regions, which represent recently diverged identity by state blocks, suggest some TE families ma...

Source: PLoS Genetics - December 22, 2023 Category: Genetics & Stem Cells Authors: Manisha Munasinghe Source Type: research