Single-Cell DNA Methylation Analysis of Chicken Lampbrush Chromosomes.

DNA methylation is an essential epigenetic regulation mechanism implicated in transcription and replication control, developmental reprogramming, retroelements silencing and other genomic processes. During mammalian development, a specific DNA methylation pattern should be established in germ cells to allow embryonic development. Less is known about germ cell DNA methylation in other species. To close this gap, we performed a single-cell methylome analysis of chicken diplotene oocytes. We comprehensively characterized methylation patterns in these cells, obtained methylation-based chicken genome segmentation and identified oocyte-specific methylated gene promoters. Our data show that despite the formation of specific transcriptionally hyperactive genome architecture in chicken diplotene oocytes, methylation patterns in these cells closely resemble genomic distribution observed in somatic tissues.