Extensive DNA methylome rearrangement during early lamprey embryogenesis

Area of Science:

• Developmental Biology
• Epigenetics
• Evolutionary Biology

Background:

• DNA methylation (5mC) is a key epigenetic regulator in vertebrates.
• Establishment of 5mC patterns during development varies significantly across species, with mammals and teleosts showing distinct remodeling strategies.

Purpose of the Study:

• To investigate the dynamics of 5mC during embryonic development in sea lamprey, a basal vertebrate.
• To understand the evolutionary origins of 5mC reprogramming in vertebrates.

Main Methods:

• 5mC quantification in sea lamprey embryos and tissues.
• Analysis of 5mC patterns in relation to programmed genome rearrangement (PGR).

Main Results:

• Discovered large-scale maternal-to-paternal epigenome remodeling affecting approximately 30% of the embryonic genome.
• Identified that this remodeling is predominantly associated with partially methylated domains.
• Demonstrated hypermethylation of sequences targeted for PGR in sperm before the process begins.

Conclusions:

• Sea lamprey exhibits extensive 5mC reprogramming during embryonic development, distinct from mammals but sharing features with other vertebrates.
• This study provides crucial insights into the evolutionary diversity of 5mC reprogramming and its role in vertebrate development.