Table 2. The cells and stages indicated by each number and their abbreviations.

Number	Cell and stage	Abbreviation (Stage)
1	preleptotene spermatocyte at stage VIII	pL (VIII)
2	leptotene spermatocyte at stage X	L (X)
3	zygotene spermatocyte at stage XII	Z (XII)
4	pachytene spermatocyte at stage I	P (I)
5	pachytene spermatocyte at stage V	P (V)
6	pachytene spermatocyte at stage VIII	P (VIII)
7	pachytene spermatocyte at stage X	P (X)
8	M phase spermatocytes at stage XII	M (XII)
9	round spermatid at stage I	R (I)
10	round spermatid at stage V	R (V)
11	round spermatid at stage VIII	R (VIII)
12	elongated spermatid at stage X	E (X)

While H3K4me2 was observed beginning in preleptotene cells (Fig 1-1B), the H3K4me3 signal was not detected between preleptotene cells to pachytene cells (Fig 1-2A, arrowheads 1–7). H3K4me3 was first detected in M-phase spermatocytes in stage XII seminiferous tubules (Fig 1-2A, arrowhead 8). The signal was broadly distributed on condensed chromosomes (Fig 1-2B, arrowhead 8). After meiosis II, the signal was detected in round spermatids at stages I to VIII, though there was no signal in the chromocenter (Fig 1-2A, arrowheads 9–11). In elongated spermatids, the signal was weak and widely detected in the whole nucleus (Fig 1-2A, arrowhead 12). Thus, localization of the H3K4me3 modification appeared later in meiosis, and the signal was weak compared to the H3K4me2 modification (Fig 1-2B).