We describe and illustrate a set of morphological landmarks for classifying mouse embryos by gross morphology from before gastrulation to the beginning of organogenesis. These landmarks are visible at the resolution of the dissecting microscope in embryos that are intact except for reflexion of Reichert's membrane. Adoption of these criteria should facilitate interpretation of both the expression patterns of genes and the consequences of experimental manipulation of embryos during early postimplantation development.

Reference

Beddington
R. S. P.
(
1992
)
In Post-Implantation Development in the Mouse.
Ciba Foundation Symposium
165
,
55
–.
Beddington
R. S. P.
,
Rashbass
P.
,
Wilson
V.
(
1992
)
Brachyury -a gene affecting mouse gastrulation and early organogenesis.
Development
1992
,
157
165
Blum
M.
,
Gaunt
S. J.
,
Cho
K. W. Y.
,
Steinbisser
H.
,
Blumberg
B.
,
Bittner
D.
,
DeRobertis
E. M.
(
1992
)
Gastrulation in the mouse: The role of the homeobox gene goosecoid.
Cell
69
,
1097
1106
Brook
F. A.
,
Estibeiro
J. P.
,
Copp
A. J.
(
1991
)
Relationship between rate at embryonic developemnt and the preponderance of cranial neural tube defects in females.
Genet. Res
58
,
76
–.
Burgoyne
P. S.
(
1993
)
A Y-chromosomal effect on blastocyst cell number in mice.
Development
117
,
341
345
Champlin
A. K.
,
Dorr
D. L.
,
Gates
A. H.
(
1973
)
Determining the stage of the estrous cycle in the mouse by the appearance of the vagina.
Biol. Reprod
8
,
491
494
Downs
K. M.
,
Martin
G. M.
,
Bishop
J. M.
(
1989
)
Contrasting patterns of myc and N- myc expression during gastrulation of the mouse embryo.
Genes Dev
3
,
860
869
Fujinaga
M.
,
Baden
J. M.
(
1992
)
Variation in development of rat embryos at the presomite period.
Teratology
45
,
661
670
Fujinaga
M.
,
Brown
N. A.
,
Baden
J. M.
(
1992
)
Comparison of staging systems for the gastrulation and early neurulation period in rodents: a proposed new system.
Teratology
46
,
183
190
Goedbloed
J. F.
(
1972
)
The embryonic and postnatal growth of rat and mouse.
Acta anat
82
,
305
336
Herrmann
B. G.
(
1991
)
Expression pattern of the Brachyury gene in whole-mount TWis /TWis mutant embryos.
Development
113
,
913
917
Jurand
A.
(
1974
)
Some aspects of the development of the notochord in mouse embryos.
J. Embryol. Exp. Morph
32
,
1
33
Lawson
K. A.
,
Pedersen
R. A.
(
1987
)
Cell fate, morphogenetic movement and population kinetics of embryonic endoderm at the time of germ layer formation in the mouse.
Development
101
,
627
652
Lawson
K. A.
,
Meneses
J.
,
Pedersen
R. A.
(
1991
)
Clonal analysis of epiblast fate during germ layer formation in the mouse embryo.
Development
113
,
891
911
Poelmann
R. E.
(
1981
)
The head process and the formation of the definitive endoderm in the mouse embryo.
Anat. Embryol
162
,
41
49
Seller
M. J.
,
Perkins-Cole
K. J.
(
1987
)
Sex difference in mouse embryonic development at neurulation.
J. Reprod. Fert
79
,
159
196
Tsunoda
Y.
,
Tokunaga
T.
,
Sugie
T.
(
1985
)
Altered sex ratio of live young after transfer of fast-and slow-developing mouse embryos.
Gamete Res
12
,
301
304
Wilkinson
D. G.
,
Bhatt
S.
,
Herrmann
B. G.
(
1990
)
Expression pattern of the mouse T gene and its role in mesoderm formation.
Nature
343
,
657
659
Yamaguchi
T. P.
,
Conlon
R. A.
,
Rossant
J.
(
1992
)
Expression of the fibroblast growth factor receptor FGFR-1/flg during gastrulation and segmentation in the mouse embryo.
Dev. Biol
152
,
75
88
This content is only available via PDF.