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-
-
- In STAGES, cell types are identified by the abbreviations below.
- For each species, under the `Show Cell Sequence Data' option, the cell
- types are arranged according to their associations within stages. The
- syntax to identify a cell is <type>-<stage>: <type> is the cell's type,
- and <stage> is the cell's stage; e.g., S7-7 refers to round spermatid
- step 7 (`S7'), found in Stage VII of the Sprague-Dawley Rat cycle.
-
-
-
-
- A = type A spermatogonium
- As = type A stem cell
- Apr = paired type A spermatogonium
- Aal = aligned type A spermatogonium
- Ad = dark spermatogonium type A - stem cell
- Ap, Ap1, Ap2 = pale spermatogonium type A - committed stem cell
- A1-A4 = 1 - 4 type A spermatogonia
- I = intermediate spermatogonium
- B = type B spermatogonium
- B1-B3 = 1 - 3 type B spermatogonia
- PL = preleptotene spermatocyte
- L = leptotene spermatocyte
- Z = zygotene spermatocyte
- P = pachytene spermatocyte
- D = diplotene/diakinetic spermatocyte
- M1, M2 = meiotic pachytene spermatocyte
- SS = secondary spermatocyte
- S1-S19 = 1 - 19 spermatids
-
-
- The following is an example of the cellular association in the
- spermatogenic cycle of the rat.
-
-
- Cells
- S15 S16 S16 S17 S17 S18 S19 S19
- S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14
- P P P P P P P P P P P P D M1/SS/M2
- A4 I I I/B B B/PL PL PL L L L Z Z P
- Aal Aal Aal Aal Aal Aal Aal A1 A1 A2 A2 A2 A3 A3
- As As As As As As As As As As As As Apr Apr
- As As
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- 1 2 3 4 5 6 7 8 9 10 11 12 13 14
- Stages
-
-
- Most of the data used for the cellular associations within stages
- were taken directly from the references. (See the `Bibliographic
- References' option at the General Menu.) In a few cases, however,
- the cell types and stage durations were estimated after reading
- several sources. There is some disagreement in the literature over
- exact stages in certain species. We have attempted to use the most
- widely accepted stage data, but it should be pointed out that there
- are two different models concerning the differentiation of
- spermatogonia, the Clermont and the Huckins (see 'Bibliographic
- References').
-
- In the rat and mouse, we use "As" to represent the stem cell
- spermatogonium, the "Apr" and "Aal" as undifferentiated
- spermatogonia (after Huckins), and the A1-A4 cells as the
- differentiated cells (after Clermont). "As" or "Ad" are used as
- the undifferentiated stem cells in all the species contained in
- STAGES. However, "Apr" (paired) and "Aal" (aligned) spermatogonia
- have not been identified for all species.
-
- The As and Apr spermatogonia do not divide synchronously within
- the cycle; therefore, as presented, the STAGES program uses a best
- estimate of the linear sequence of the undifferentiated and stem
- cell spermatogonia in all the animals.