Telfer, Evelyn E

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Evelyn E Telfer

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Reproductive Biology and 
Endocrinology
ssOpen AcceDebate
Germline stem cells in the postnatal mammalian ovary: A 
phenomenon of prosimian primates and mice?
Evelyn E Telfer*
Address: Institute of Cell and Molecular Biology, University of Edinburgh, The Darwin Building Mayfield Road, Edinburgh EH9 3JR, United 
Kingdom
Email: Evelyn E Telfer* - Evelyn.Telfer@ed.ac.uk
* Corresponding author    
The paper by Johnson et al. "Germ line stem cells and fol-
licular renewal in the postnatal mammalian ovary" pub-
lished in Nature on the 11th of March [1] suggests that a
population of germ line stem cells exist within the adult
mouse ovary and that oocyte numbers are regulated by a
balance of activation of these cells and cell death. This
paper should be viewed in its historical context as it re-
ignites a debate that was thought to have been settled in
the 1950s but one in which exceptions to the accepted
dogma have previously been found.
Whether or not germ cells were fixed early in life or capa-
ble of continuing formation in adult life was a debate that
was raised in the 1920's. In the 1920s the general view was
that the oocyte supply was fixed [2] but this was chal-
lenged by Allen in 1923 [3] who believed he had evidence
to support the theory that the formation of oocytes con-
tinued throughout reproductive life. It was proposed that
cyclical proliferation of the germinal epithelium gave rise
to oocytes [3-5]. This was a widely held view until the
1950s when Zuckerman (1951) [6] showed by extensive
studies based on differential counting of follicles that
oocytes were not produced throughout the life-span in
most mammals. Further evidence using tritiated thymi-
dine labelling of oocyte nuclei supported the view that
juvenile and adult ovaries are direct descendants of the
fetal germ cells and that germ cells do not increase in
number throughout life [7-9]. Since these experiments the
view that the oocyte population is fixed has been sup-
ported by numerous studies that have monitored prolifer-
ation of somatic cells throughout ovarian development in
several mammalian species with none reporting signs of
proliferation of putative germ cells. However, exceptions
to this have previously been found in mammals; in some
species of prosimian primates (Loris tardigradus lydekkeri-
anus and Nycticebus coucang), the most ancient of primate
families, mitotically active germ cells have been found in
adult ovaries [10,11]. These studies found that germ cells
clustered in nests within the ovarian cortex incorporated
tritiated thymidine. The question of whether any of these
proliferating germ cells pass through follicular growth and
ovulation remains unanswered and the original studies
provided no evidence to suggest that they did. The John-
son et al. [1] paper follows in a long line of studies in this
area and forces us to reassess long held beliefs. The mouse
study may suggest that the prosimian primates are not the
only mammals to exhibit this phenomenon but the pres-
ence of such cells in other mammalian species remains to
be proven. If the dogma is to be debunked and a new one
accepted, at least in the mouse, it is sure to be challenged
and tested, as should all dogma. This is the way of science
and scientists.
References
1. Johnson J, Canning J, Kaneko T, Pru JK, Tilly JL: Germline stem cells
and follicular renewal in the postnatal mammalian ovary.
Nature 2004, 428:145-150.
2. Pearl R, Schoppe WE: Studies on the physiology of reproduc-
tion in the domestic fowl. J Exp Zool 1921, 34:101-118.
3. Allen E: Ovogenesis during sexual maturity. Am J Anat 1923,
31:439-481.
4. Evans HM, Swezy O: Ovogenesis and the normal follicular cycle
in adult mammalia. Mem Univ Calif 1931, 9:119-224.
5. Allen E, Creadick RN: Ovogenesis during sexual maturity. The
first stage, mitosis in the germinal epithelium, as shown by
the colchicine technique. Anat Rec 1937, 69:191-195.
6. Zuckerman S: The number of oocytes in the mature ovary.
Recent Prog Horm Res 1951, 6:63-109.
Published: 18 May 2004
Reproductive Biology and Endocrinology 2004, 2:24
Received: 15 April 2004
Accepted: 18 May 2004
This article is available from: http://www.rbej.com/content/2/1/24
© 2004 Telfer; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media 
for any purpose, provided this notice is preserved along with the article's original URL.Page 1 of 2
(page number not for citation purposes)
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7. Rudkin GT, Griech HA: On the persistence of oocyte nuclei
from fetus to maturity in the laboratory mouse. J Cell Biol 1962,
12:169-175.
8. Borum K: Oogenesis in the mouse. A study of the origin of the
mature ova. Exp Cell Res 1967, 45:39-47.
9. Peters H, Crone M: DNA synthesis in oocytes of mammals. Arch
Anat Microsc Morphol Exp 1967, 56:160-170.
10. Duke KL: Ovogenetic activity of the fetal-type in the ovary of
the adult slow loris, Nycticebus coucang. Folia Primatol (Basel)
1967, 7:150-154.
11. David GF, Anand Kumar TC, Baker TG: Uptake of tritiated thy-
midine by primordial germinal cells in the ovaries of the
adult slender loris. J Reprod Fertil 1974, 41:447-451.Page 2 of 2
(page number not for citation purposes)


Telfer Evelyn E

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