Epigenetic processes in the male germline

Area of Science:

• Reproductive biology
• Epigenetics
• Spermatozoa biology

Background:

• Sperm chromatin undergoes extensive modifications: DNA methylation erasure/establishment, histone removal, and protamine replacement.
• These changes facilitate DNA packaging, transcriptional silencing during spermatogenesis, and genome reactivation post-fertilization.
• Recent advances challenge established views on sperm DNA packaging and epigenetic states.

Purpose of the Study:

• To review recent findings and controversies in male germline epigenetics.
• Focus on DNA methylation dynamics, non-coding RNAs, sperm chromatin packaging, and transgenerational inheritance.
• Highlight associations between sperm DNA packaging defects and disease/fertility.

Main Methods:

• Literature review of recent findings and controversies.
• Focus on high-throughput sequencing technologies enabling new discoveries.
• Analysis of studies on DNA methylation, non-coding RNAs, and chromatin packaging.

Main Results:

• Not all histones are replaced by protamines in spermatozoa.
• Various RNA species detected in transcriptionally quiescent spermatozoa.
• Evidence suggests potential environmental modifications of sperm epigenetics and transgenerational epigenetic inheritance.

Conclusions:

• Sperm epigenetics is a dynamic field with ongoing research and debate.
• Non-coding RNAs play increasingly recognized roles in male germline.
• Sperm chromatin packaging defects are linked to health and fertility outcomes.