What the human sperm methylome tells us

Abstract

Aim: To characterize the sperm methylome in semen samples from 19 donors with proven fertility. Materials & methods: Bisulfite-converted sperm DNA was hybridized on the HumanMethylation450 Infinium BeadChip platform. CpG fluorescence intensities were extracted and converted to β-values. Results: The sperm methylome is highly homogeneous and hypomethylated. Genes with hypomethylated promoters are ontologically associated to biological functions related to spermatogenesis and embryogenesis. Sex chromosomes are the most hypomethylated chromosomes, supporting data that indicated their essential role in spermatogenesis. A total of 94 genes are resistant to demethylation, being strong candidates for transgenerational inheritance. Conclusion: Spermatozoa carry a homogeneous methylation profile that is a footprint of past events (spermatogenesis), is designed to facilitate future events (embryogenesis) and has a possible influence in the adult life (transgenerational effects).

Keywords::

• DNA methylation
• embryogenesis
• methylome
• miRNA
• piRNA
• sex chromosomes
• spermatogenesis
• spermatozoa
• transgenerational epigenetic inheritance

Acknowledgements

The authors wish to thank the staff of The Spanish National Genotyping Centre (CeGen, www.cegen.org) (Madrid Node) for their technical assistance in the analysis of samples using the HumanMethylation450 Infinium BeadChip. This manuscript has been proofread by Proof-Reading-Service.org.

Financial & competing interests disclosure

This work was supported by Projects PS09/00330 (Gobierno de España, Spain) and SGR2014-524 2 (Generalitat de Catalunya, Spain). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at: www.tandfonline.com/doi/full/10.2217/epi-2017-0049

Additional information

Funding

This work was supported by Projects PS09/00330 (Gobierno de España, Spain) and SGR2014-524 2 (Generalitat de Catalunya, Spain). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.