Ontogenetic Survey of Histone Modifications in an Annelid

Table 1

Summary of histones and epigenetic modifications during development of Polydora cornuta. The modifications listed were common to both morphs (i.e., were observed in both adelphophagic and planktotrophic young). + = modification present; − = modification absent; blank = no sample. h = head, m = mouth, p = pygidium, vc = ventral cells.

Modification	Developmental stage
	Oocyte	2–4 cells	8 cells	32 cells	Blastula	Gastrula	Trochophore	Metatrochophore	3 chaetigers	5–12 chaetigers	Adult
Histones	+	+	+	+	+	+	+	+	+	+	+
H3K14ac	−	−	+; (not D)	+	+	+*; (m)	+*; (m, vc, p)	+*; (m, vc, p)	+*; (m, vc, p)	+*; (m, vc, p)	Some tissues
H3K9me	−	−	+	+	+*; (h)	+*; (h)	+	+	+	+	Some tissues
H3K4me2	−		+	+	+	+	+	+	+	+	Some tissues
H4K20me2							−		−		−

*interpreted as hyperacetylation or hypermethylation in indicated cell lineages (see text).