scholarly journals Haploid Embryos: Being Like Mommy or Like Daddy?

Author(s):  
Thomas Widiez
Keyword(s):  
Development ◽  
1974 ◽  
Vol 31 (3) ◽  
pp. 635-642
Author(s):  
M. H. Kaufman ◽  
R. L. Gardner

Parthenogenetic mouse embryos were selected following in vitro activation, and transferred to the oviducts of pseudopregnant recipients. Decidua was evoked by 50–56% of diploid parthenogenones compared to 35·1% of haploid embryos with a single pronucleus, 37·5% of immediate cleavage eggs and 77% of fertilized eggs (controls). On day 4, 58·7% of diploid parthenogenones were morphologically normal morulae or blastocysts; over 90% of these ‘normal’ embryos evoked decidua when retransferred to recipients compared to 8·9% of abnormal embryos flushed from the ‘transfer’ sides, suggesting that only ‘normal’ embryos could evoke decidua. Potentially diploid parthenogenones remained diploid on chromosomal examination on day 4.


Development ◽  
1972 ◽  
Vol 28 (2) ◽  
pp. 449-462
Author(s):  
Louie Hamilton ◽  
P. H. Tuft

The uptake of water by haploid and diploid sibling embryos of Xenopus laevis has been investigated by measuring the density changes which occur during the development of intact embryos from the blastula to the late tail-bud stage, and of explants from which most of the presumptive endoderm has been removed. The results show that up to the mid-gastrula stage there is no difference between the haploid and diploid embryos; but from then on, whereas the diploid volume increases steadily, the haploid gastrulae undergo a series of cyclical volume changes due to loss of fluid through the blastopore. It is concluded that this is the result of an excessive inflow of water through the haploid ectoderm, because it was found that the volume of haploid ectodermal explants increased much more rapidly than the volume of similar diploid explants. Excess flow through the haploid ectoderm also accounts for other characteristics of the haploid syndrome – microcephaly and lordosis. It is suggested that it is the doubling of the cell number in haploid embryos with the consequent 25% increase in aggregate cell membrane area which accounts for the difference between the uptake of water by the two types of embryos. It is also suggested that changes in the rate of water flow through the ectoderm and endoderm which are thought to account for the accumulation of water in the blastocoel and archenteron in the normal diploid embryo arise in a similar way.


Development ◽  
1975 ◽  
Vol 34 (2) ◽  
pp. 387-405
Author(s):  
S. A. Iles ◽  
M. W. McBurney ◽  
S. R. Bramwell ◽  
Z. A. Deussen ◽  
C. F. Graham

Mouse eggs were activated with hyaluronidase in vitro and subsequently transferred to the oviduct. In the female reproductive tract they formed morulae and blastocysts which died soon after implantation. Haploid blastocysts were transferred beneath the kidney capsule and here some formed disorganized egg-cylinder structures in a week. Morulae and blastocysts from haploid and diploid parthenogenones were also transferred beneath the testis capsule. Two to four months later the growths which had formed were sectioned. They contained neural tissue, pigment, keratinized epithelium, glandular epithelium, ciliated epithelium, cartilage, bone, muscle, adipose tissue, and haemopoietic tissue. The range of cell types was similar to that produced by fertilized control blastocysts except that the parthenogenones did not form identifiable yolk-sac carcinoma or embryonal carcinomacells. The growths from haploid and diploid parthenogenones in the testis were stained with Feulgen and their DNA content measured. Growths from diploid embryos contained the normal diploid amount of DNA while growths from haploid embryos contained less than this amount. Cell cultures were prepared from the growths. The cells which were investigated contained no Y chromosome, suggesting that they were derived from the embryonic cells rather than the cells of the male host. These cells contained a near diploid chromosome number, although some of them were originally derived from haploid embryos.


Development ◽  
1977 ◽  
Vol 38 (1) ◽  
pp. 187-202
Author(s):  
Andrzej K. Tarkowski

F1(CBA × C57BL'10) mouse eggs originating from spontaneous or induced ovulation and fertilized by CBA-T6T6 or PO spermatozoa were bisected with a glass needle into halves each containing a pronucleus. This technique offers a unique opportunity of producing both androgenetic and gynogenetic haploid embryos from one egg. Out of 600 operated eggs, in 406 (67·7%) both halves survived. During 96 h of culture in vitro the fragments were inspected once daily and finally examined in air-dried preparations. Eighty-seven per cent of halves underwent first cleavage but their further development was to a large extent affected by extrinsic factors connected with experimental procedure (mainly by suboptimal and variable culture conditions) and by the origin of eggs (those from spontaneous ovulation being superior). For this reason developmental capabilities of egg halves were assessed in a selected group of pairs in which at least one partner reached the stage of four or more blastomeres. The observed ratio between pairs with both or only one sister embryo developing successfully suggests that androgenetic embryos carrying Y rather than X chromosome can cleave twice but do not survive beyond 4-cell stage. None of the metaphase plates from older embryos contained a Y chromosome. These observations imply that the X chromosome is genetically active during early cleavage and that a full haploid set is required for preimplantation development to be completed. Formation of blastocysts varied from batch to batch, with an average of 12·8% and maximal incidence of 29·5% . In 34 pairs both fragments developed beyond the 4-cell stage but in only one case did both form blastocysts. Haploid blastocysts were composed of 27 cells on average which was about a half of the number of cells in control diploid zona-free whole eggs. Ten out of 51 embryos with metaphase plates proved to be haploid/diploid mosaics.


Development ◽  
1980 ◽  
Vol 59 (1) ◽  
pp. 249-261
Author(s):  
Mark S. Ellinger ◽  
Judith A. Murphy

External surfaces of haploid and diploid embryos of Bombina orientalis were examined with the scanning electron microscope to determine the possible contribution of cellular morphology to the amphibian haploid syndrome. Cellular anomalies were prevalent in all surface areas of haploid embryos. The epithelium appeared uneven due to the displacement of ciliated cells and the rounded apical surfaces of the non-ciliated cells. The ratio of ciliated to non-ciliated cells was altered in comparison to diploid embryos. Cells of the gill filaments and adhesive organs were abnormal in morphology, and the adhesive organs themselves were fused into a single large rudiment in haploid embryos. Uniformity of cell size was markedly reduced in head regions of haploid embryos with severe microcephaly. Haploid and diploid embryos elaborated mucoid matrices over the surface cells when removed from the fertilization envelope. It is apparent that aberrant cellular morphologies are widespread in haploid embryos, and it is likely that these defects are major contributors to the gross morphological anomalies of the haploid syndrome.


1986 ◽  
Vol 64 (9) ◽  
pp. 2107-2112 ◽  
Author(s):  
L. S. Kott ◽  
S. Flack ◽  
K. J. Kasha

Cells of haploid barley embryos (Hordeum vulgare L. 'Bruce', 'Perth', and 'Klages') and callus cells originating from embryos were cytophotometrically examined to determine the ploidy level. Specific embryo tissues regularly exhibited predictable ploidies and smaller embryos had a higher percentage of haploid cells than larger embryos of the same age. The predominantly haploid cells of the scutellar epidermis of the embryo initiated callus which generally, at least initially, was haploid. Monitoring of the ploidy evolution of these haploid calli showed that over a 6-month period each line exhibited its own unique rate of polyploidization, although lines of the same cultivar showed similar trends. Accumulation of cells at the diploid level was often a characteristic of these cultures.


2016 ◽  
Vol 52 (6) ◽  
pp. 590-597 ◽  
Author(s):  
Angelika Noga ◽  
Edyta Skrzypek ◽  
Marzena Warchoł ◽  
Ilona Czyczyło-Mysza ◽  
Kinga Dziurka ◽  
...  

1997 ◽  
Vol 48 (8) ◽  
pp. 1207 ◽  
Author(s):  
K. Suenaga ◽  
A. R. Morshedi ◽  
N. L. Darvey

In order to reduce the labour for wheat haploid production through wheat maize crosses, several emasculation methods were investigated in combination with the ‘spike culture method’. Although the standard method whereby wheat spikes were hand-emasculated and pollinated on the day of anthesis gave a higher efficiency, the ‘non-emasculation method’ gave a comparable response. The use of the non-emasculation method and spike culture could eliminate much of the labour required for emasculation and treatment with 2,4-D, which is normally applied by injection into wheat internodes or by dropping onto florets after pollination with maize. Most of the selfed seeds were easily identified by the presence of endosperm, and the probability of contamination by the embryos originating from selfing among the presumptive haploid embryos in the non-emasculation method was very low. Twenty-seven Australian wheat cultivars were investigated for haploid production through wheat × maize crosses using the non-emasculation and spike culture methods. All of the 27 cultivars produced embryos after crossing with maize, with a mean efficiency of 33·1% (embryos/florets). Except for one cultivar, Tincurrin, plants were recovered from all of the cultivars (average of 61·5% including Tinccurin). This innovation of haploid production through wheat maize crosses is discussed.


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