Fig. 4

Genomic features and epigenetic patterning in the maternal oocyte are associated with ERVK LTR expression patterns in extra-embryonic tissues. a CpG content was compared between ERVK LTRs that were transcriptionally active in extra-embryonic tissues, including the subset of non-canonically imprinted ERVKs (N = 40, blue dots) and all mappable ERVK LTRs (N = 334,322) (p < 5E−10, Welch two-sample t test). b The proportion of transcriptionally active ERVK LTRs in extra-embryonic tissues (N = 40) within 3 kb of a transcription start site (TSS) on the same or opposing strand was compared to all mappable ERVK LTRs (N = 334,322) (chi-square statistic, p < 0.0001). c The proportion of transcriptionally active non-canonical imprinted ERVK LTRs (N = 8) and extra-embryonic active ERVK LTRs (N = 32) overlapping epigenetic modifications in GV oocytes was compared to a random subset of mappable ERVK LTRs (N = 100) (chi-square statistic, p = 0.0002 and p = 0.0001, respectively)