We investigated the origin of XX sex reversal in the insectivorous mole Talpa occidentalis. Cytogenetic, histological and hormonal studies indicate that all XX individuals analyzed from two different populations are true hermaphrodites, with ovotestes. This suggests that XX sex reversal may be the norm in this species. The intersexes are functional fertile females and the trait is transmitted and maintained in the population. Intersexes lack the Y chromosome gene SRY (sex determining region Y gene), shown to be the testis determining gene. These results suggest that XX intersex moles may have arisen from a mutation of a gene located downstream from SRY/TDY in the testis determining pathway.

Behringer
R. R.
,
Cate
R. L.
,
Froelick
G. J.
,
Palmiter
R. D.
,
Brinster
R. L.
(
1990
)
Abnormal sexual development in transgenic mice chronically expressing Mullerian inhibiting substance.
Nature
345
,
167
170
Berkovitz
G. D.
,
Fechner
P. Y.
,
Marcantonio
S. M.
,
Bland
G.
,
Stetten
G.
,
Goodfellow
P. N.
,
Smith
K. D.
,
Migeon
C. J.
(
1992
)
The role of the sex-determining region of the Y chromosome (SRY) in the etiology of 46, XX true hermaphroditism.
Hum. Genet
88
,
411
416
Burgos
M.
,
Jimenez
R.
,
Díaz de la Guardia
R.
(
1986
)
A rapid, simple and reliable combined method for G-banding mammalian and human chromosomes.
Stain Technol
61
,
257
260
Burgos
M.
,
Jimenez
R.
,
Díaz de la Guardia
R.
(
1988
)
XY females in Microtus cabrerae (Rodentia, Microtidae).
Cytogenet. Cell Genet
49
,
275
277
Burgoyne
P. S.
,
Buehr
M.
,
Koopman
P.
,
Rossant
J.
,
McLaren
A.
(
1988
)
Cell-autonomous action of the testis-determining gene: Sertoli cells are exclusively XY in XX-XY chimeric mouse testes.
Development
102
,
443
450
Cattanach
B. M.
,
Evans
E. P.
,
Burtenshow
M. D.
,
Barlow
J.
(
1982
)
Male, female and intersex development in mice of identical chromosome constitution.
Nature
300
,
445
446
Crumeyrolle-Arias
M.
,
Scheib
D.
,
Ascheim
P.
(
1976
)
Light and electron microscopy of the ovarian interstitial tissue in the senile rat: Normal aspect and response to HCG of ‘deficiency cells’ and ‘epithelial cords’.
Gerontology
22
,
185
204
Fredga
K.
,
Gropp
A.
,
Winking
H.
,
Frank
F.
(
1976
)
Fertile XX and XY-type females in the wood lemming (Myopus schisticolor).
Nature
261
,
255
257
Goodfellow
P. N.
,
Darling
S. M.
(
1988
)
Genetics of sex determination in man and mouse.
Development
102
,
251
258
Guaellaen
G.
,
Casanova
M.
,
Bishop
C.
,
Geldwerth
D.
,
Andre
G.
,
Fellous
M.
,
Weissenbach
J.
(
1984
)
Human XX males with single copy DNA fragments.
Nature
307
,
172
173
Jimenez
R.
,
Burgos
M.
,
Caballero
L.
,
Díaz de la Guardia
R.
(
1988
)
Sex reversal in a wild population of Talpa occidentalis (Insectivora, Mammalia).
Genet. Res
52
,
135
140
Jimenez
R.
,
Burgos
M.
,
Sánchez
A.
,
Díaz de la Guardia
R.
(
1990
)
The reproductive cycle of Talpa occidentalis in the southeastern Iberian Peninsula.
Acta Theriol
35
,
1
2
McLaren
A.
(
1990
)
Of MIS and the mouse.
Nature
345
,
111
–.
McLaren
A.
,
Monk
M.
(
1982
)
Fertile females produced by inactivation of an X chromosome of ‘sex reversed’ mice.
Nature
300
,
446
448
Nistal
M.
,
Paniagua
R.
,
Regadera
J.
,
Santamaría
L.
,
Amat
P.
(
1986
)
A quantitative morphological study of human Leydig cells from birth to adulthood.
Cell. Tissue Res
246
,
229
236
Page
D.C.
(
1986
)
Sex reversal: Deletion mapping the male determining function of the human Y chromosome.
Cold Spring Harbor Symp. Quant. Biol
51
,
229
235
Page
D. C.
,
Mosher
R.
,
Simpson
E. M.
,
Fisher
E. M. C.
,
Mardon
G.
,
Pollack
F.
,
McGillivray
B.
,
Chapelle de la
A.
,
Brown
L. G.
(
1987
)
The sex-determining region of the human Y chromosome encodes a finger protein.
Cell
51
,
1091
1104
Palmer
S. J.
,
Burgoyne
P. S.
(
1991
)
XY follicle cells in the ovaries of X0/XY and X0/XY/XYY mosaic mice.
Development
111
,
1017
1019
Palmer
S. J.
,
Burgoyne
P. S.
(
1991
)
In situ analysis of fetal, prepuberal and adult XX-XY chimaeric mouse testes: Sertoli cells are predominantly, but not exclusively, XY.
Development
112
,
265
268
Patek
C. E.
,
Kerr
J. B.
,
Gosden
R. G.
,
Jones
K. W.
,
Hardy
K.
,
Muggleton-Harris
A. L.
,
Handyside
A. H.
,
Whittingham
D. G.
,
Hooper
M. L.
(
1991
)
Sex chimaerism, fertility and sex determination in the mouse.
Development
113
,
311
325
Selden
J. R.
,
Moorhead
P. S.
,
Koo
G. C.
,
Wachtell
S. S.
,
Haskings
M. E.
,
Patterson
D. F.
(
1984
)
Inherited XX sex reversal in the cocker spaniel dog.
Hum. Genet
67
,
62
69
Sharp
A. J.
,
Wachtell
S. S.
,
Benirschke
K.
(
1980
)
H-Y antigen in a fertile female horse.
J. Reprod. Fertil
58
,
157
160
Sinclair
A. H.
,
Berta
P.
,
Palmer
M. S.
,
Hawkins
J. R.
,
Griffiths
B. L.
,
Smith
M. J.
,
Foster
J. W.
,
Frischauf
A. M.
,
Lovell-Badge
R.
,
Goodfellow
P. N.
(
1990
)
A gene from the human sex-determining region encodes a protein with homology to a conserved DNA-binding motif.
Nature
346
,
240
244
Taketo-Hosotani
T.
,
Merchant-Larios
H.
,
Thau
R.
,
Koide
S. S.
(
1985
)
Testicular cell differentiation in fetal mouse ovaries following transplantation into adult male mice.
J. Exp. Zool
236
,
229
237
Tran
D.
,
Josso
N.
(
1982
)
Localisation of anti-Mullerian hormone in the rough endoplasmic reticulum of the developing bovine Sertoli cells using immunocytochemistry with a monoclonal antibody.
Endocrinology
111
,
1562
1567
Vigier
B.
,
Watrin
F.
,
Magre
S.
,
Tran
D.
,
Josso
N.
(
1987
)
Purified bovine AMH induces a characteristic freemartin effect in fetal rat prospective ovaries exposed to it in vitro.
Development
100
,
43
55
This content is only available via PDF.