The genomic ecosystem of transposable elements in maize.

Area of Science:

• Genomics
• Molecular Biology
• Evolutionary Biology

Background:

• Transposable elements (TEs) comprise the majority of flowering plant genomes, significantly shaping genome structure through transposition.
• Maize genome sequencing reveals over 85% of its DNA originates from past transposition events.
• Previous genome-wide analyses often treated TEs as uniform relics, masking their evolutionary dynamics and host interactions.

Purpose of the Study:

• To investigate the family-level dynamics of transposable elements (TEs) in the maize genome using an updated annotation of structurally intact TEs.
• To model the relationship between genomic environment attributes and the survival of TE copies and families.
• To challenge the notion of TEs as solely "junk DNA" by exploring their diverse survival strategies.

Main Methods:

• Utilized an updated annotation of structurally intact transposable elements (TEs) in the maize reference genome.
• Integrated diverse data including TE coding capacity, expression, methylation, and features of their insertion sites.
• Modeled the interplay between genomic environment characteristics and the persistence of TE copies and families.

Main Results:

• Identified diverse survival strategies among different transposable element (TE) families in maize, refuting their classification as homogeneous "junk DNA".
• Demonstrated that TE family survival is influenced by attributes of their genomic environment.
• Revealed a rich genomic ecology where each TE family occupies a distinct evolutionary niche.

Conclusions:

• Transposable element (TE) impact is family- and context-dependent, necessitating a family-level ecological perspective.
• Understanding TE family ecology refines predictions of their role in generating genetic and phenotypic diversity.
• TEs exhibit diverse evolutionary strategies, contributing significantly to genome evolution and variation.