EXPERIMENTAL ALTERATIONS OF THE DEVELOPMENTAL
CYTOGENETIC MECHANISMS IN MULBERRY SILKWORMS:
ARTIFICIAL PARTHENOGENESIS, POLYPLOIDY,
GYNOGENESIS, AND ANDROGENESIS
B. L. ASTAUROV
Filatov Laboratory oj Experimental
Embryology,
Severtzov
Institute
of Animal Morphology, Academy of Sciences, USSR
I. Introduction and Brief Historical Survey
200
A. Introductory Remarks
200
B. Short Historical Survey
202
II. Normal Cytogenetic Mechanism of Gametogenesis and Early
Development of the Silkworm
204
III. Alterations of Developmental Cytogenetic Mechanisms in the
Unfertilized Egg
206
A. Rudimentary Spontaneous (Natural) Parthenogenesis . . . .
206
B. Artificial Parthenogenesis
215
C. Artificial Parthenogenesis by Heat-Shock Treatment . . . .
217
IV. Parthenogenesis and Hybridization
225
A. Ability to Undergo Artificial Parthenogenesis in Pure Races
and Their F* Hybrids
225
B. Heat Parthenogenesis in Interspecific Reciprocal Hybrids
Bombyx mon L. X Bombyx mandanna Moore
225
C. Is Hybrid Vigor a Cause or a Consequence of the Ability to
Undergo Parthenogenesis?
226
V. Parthenogenesis and Polyploidy
227
A. Correlation between Parthenogenesis and Polyploidy . . . .
227
B. Somatic Polyploidization and Mixoploidy; Tetraploid Thelytokous
Parthenogenesis
227
C. Parthenogenetic Reproduction of Tetraploids and the Origin
of 4 n Clones
229
D. Mating of 4 n Females and Bisexual Production of Triploid
Females and Males
229
E. Triploid Heat Parthenogenesis and Triploid Clones . . . .
232
F. Partial Fertility of 3 n Parthenofemales and 3 n/6 n Mixoploidy
.
233
G. Production of a Self-Reproducing Bisexual Allopolyploid Strain
.
236
VI. Alterations of the Cytogenetic Mechanism of Maturation and
Fertilization in the Just-Inseminated Egg
239
A. Diploid Gynogenesis
239
B. Dispermic Androgenesis
240
C. Mosaicism and Gynandromorphism
248
VII. In Place of a Conclusion
250
References
253
199