Complex sentence: DNA Methylation patterns are largely erased and then re-established between generations in mammals whereby almost all of the methylations from the parents are erased, first during gametogenesis, and again in early embryogenesis, with demethylation and remethylation occurring each time.
Split into simpler sentences: DNA Methylation patterns are largely erased and then re-established between generations in mammals. Almost all of the methylations from the parents are erased, first during gametogenesis, and again in early embryogenesis, with demethylation and remethylation occurring each time.