• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.15-21
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• 1999

The aim of the present study was to determine the effect of paternal sex chromosome on early development of buffalo embryos fertilized and cultured in vitro. Embryos were produced in vitro from abattoir derived buffalo oocytes. The cleaved embryos were cocultured with buffalo oviductal epithelial cells and evaluated on day 7 under the phase contrast microscope to classify development. The embryos which reached the morula/blastocyst stage were fast developing, the embryos which were at 16-32 cell stage were medium developing and the embryos below 16 cell stage were slow developing. The embryos which showed some fragmentation in the blastomeres or degenerated blastomeres, were degenerating. Sex of emberyos (n=159) was determined using PCR for amplification of a male specific BRY. 1 (301 bp) and a buffalo specific satellite DNA (216 bp) fragments. The results thus obtained show that 1) X and Y chromosome bearing sperms fertilize oocytes to give almost equal numbers of cleaved XX and XY embryos, 2) male embryos develop faster than female embryos to reach advanced stage and 3) degeneration of buffalo embryos is not linked with the paternal sex chromosome. We suggest that faster development of males is due to differential processing of X and Y chromosome within the zygote for its activation and / or differential expression of genes on paternal sex chromosome sex chromosome during development of buffalo embryos fertilized and cultured in vitro which may be attributed to a combination of genetic and environmental factors.

• The Korean Journal of Zoology
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• v.13 no.1
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• pp.15-20
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• 1970

The present study was undertaken in an attempt to see if the segregation frequency of a third chromosome was changed by changing the sex chromosome which were free of SD in the second chromosome. The eight genotype males having different sex chromosome constitution each were constructed by appropriate matings and the two standard laboratory stocks of Drosophila melanogaster, e and se were used as the third chromosome recessive markers for the present experiment. The results of the present investigation are given below: 1. The k values which are the proportion of the se third chromosomes recovered among progeny flies from the mating of se/e males to e females were highly signiicantly different among the four genotypes and between the two sexes,and the interaction of genotype and sex was significantly different. Thus the setregation frequency of the se third chromosome in the male, when made heterozygous with the e third chromosome, was dependent upon the sex chromosome constitution. 2. Both of the k(Woman) and the k(man) remains roughly constant among genotypes. 3. The sex ratio o the se progeny class was highly significantly heterogeneous among the four genotypes but it was homogeneous for the e progeny class. 4. The values of the k(man) and the sex ratio of the se progeny class, on the average, were higher than that of the k(Woman) and of the e progeny class, respectively. 5. Those phenomena suggest that some sort of prezygotic selection could be operating such that the combination of the e third chromosome and the Y chromosome tends to be eliminated before fertilization. This tendency argues for a re-examination of the viability estimations of Drosophila melanogaster.

• The Korean Journal of Zoology
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• v.39 no.1
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• pp.75-88
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• 1996

OTF9-63 (OTF9) and P19S1O1A1 (P19) embryonal carcinoma (EC) cells were examined for their ability to produce the readivation of inactive X chromosomes from somatic cells. They were hybridized with various somatic cells and resulting HATr EC-somatic cell clones were analysed for their morphology, chromosomal replication pafterns and expression proffies of X-linked and distantiy located genes, Hprt and Pgk-1. The results demonstrated that 0RF9 cells could reactivate the inactive X chromosome whereas P19 cells could not. In adition, EC-somatic cell hybrids tended to reduce the number of sex chromosomes in long-term culture, resulting m 1:2 ratio of sex chromosomes to autosomes The use of EC cell hybrids provides an experimental system for studying the mechanism(s) of the X-reactivatio that is initiated and maintained from meiotic prophase of oogenesis to early embryogenesis.

• Toxicological Research
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• v.33 no.4
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• pp.315-323
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• 2017

Preconceptual sex selection is still a highly debatable process whereby X- and Y-chromosome-bearing spermatozoa are isolated prior to fertilization of the oocyte. Although various separation techniques are available, none can guarantee 100% accuracy. The aim of this study was to separate X- and Y-chromosome-bearing spermatozoa using methods based on the viability difference between the X- and Y-chromosome-bearing spermatozoa. A total of 18 experimental semen samples were used, written consent was obtained from all donors and results were analysed in a blinded fashion. Spermatozoa were exposed to different pH values (5.5, 6.5, 7.5, 8.5, and 9.5), increased temperatures ($37^{\circ}C$, $41^{\circ}C$, and $45^{\circ}C$) and ROS level ($50{\mu}M$, $750{\mu}M$, and $1,000{\mu}M$). The live and dead cell separation was done through a modified swim-up technique. Changes in the sex-chromosome ratio of samples were established by double-label fluorescent in situ hybridization (FISH) before and after processing. The results indicated successful enrichment of X-chromosome-bearing spermatozoa upon incubation in acidic media, increased temperatures, and elevated $H_2O_2$. This study demonstrated the potential role for exploring the physiological differences between X-and Y-chromosome-bearing spermatozoa in the development of preconceptual gender selection.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.179-190
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• 1996

Sexing and developing from splitted embryos which were fertilized in vitro implicate a possibility of production of the superior and sex controlled individuals. This study was carried out to investigate the production of transferable late blastocysts from in vitro fertilized embryos and to analyze sex by chromosome analysis from same embryos. In results, the ratio of cleavage and fertility of bovine follicular oocytes matured in vitro was 90% in co-cultured with granulosa cells. The competence of embryonic development from in vitro matured and fertilized bovine oocytes was 38% in co-cultured with bovine oviductal epithelial cells. To produce a lot of transferable embryos, therefore, the best conditon of culture system was co-cultured with granulosa cells for immature bovine oocytes and then co-cultured with bovine oviductal eptithelial cells for matured and fertilized oocytes. In chromosome analysis, 93% of in vitro fertilized embryos were very important aspect in chromosome preparation from bovine embryos such as duration of colcemid treatment, weakening of zona pellucida, methods of hypotonic treatment and fixation treatment.

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.225-230
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• 2009

Sex-sorting of sperm is an assisted reproductive technology (ART) used by the livestock industry for the mass production of animals of a desired sex. The standard method for sorting sperm is the detection of DNA content differences between X and Y chromosome-bearing sperm by flow cytometry. However, this method has variable efficiency and therefore requires verification by a second method. We have developed a sex determination method based on quantitative real-time polymerase chain reaction (qPCR) of the porcine amelogenin (AMEL) gene. The AMEL gene is present on both the X and the Y chromosome, but the length and sequence of its noncoding regions differ between the X and Y chromosomes. By measuring the threshold cycle (Ct) of qPCR, we were able to calculate the relative frequency of X chromosome. Two sets of AMEL primers were used in these studies. One set (AME) targeted AMEL gene sequences present in both X and Y chromosome, but produced PCR products of different lengths for each chromosome. The other set (AXR) bound to AMEL gene sequences present on the X chromosome but absent esholthe Y-chromosome. Relative product levels were calculated by normalizing the AXR fluorescence to the AME fluorescence. The AMEL method accurately predicted the sex ratios of boar sperm, demonstrating that it has potential value as a sex determination method.

• Journal of Embryo Transfer
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• v.11 no.3
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• pp.283-289
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• 1996

This study was carried out to determine the sex of genomic and embryonic DNA using polymerase chain reaction(PCR). Bovine specific(216bp) and Y chromosome speicific DNA primers(l4lbp) were synthesized and tested for sexing. Bovine embryos used in this study were produced by in vitro fertilization. Few blastomeres for PCR were bisected by nicromanipulator and demi -embryos were cultured in TCM 199 medium containing 0.1% of solcoseryl. The results obtained were as follows; 1. Average optical density of genomic DNA extracted from blood of Hanwoo was 1.79$\pm$ 0.14. 2. 2. The ratio of the demi-embryos developed to blastocyst was 62.1 and 81.9% in morula and blastocyst, respectively. 3. When DNA of 2~4, 5~10 and more than 11 blastomeres was amplified with Y chromosome specific DNA primer by PCR, appreance rate of Y specific DNA band was 16.7, 46.2 and 40.0%, respectively. At least 5 to 10 blastomeres were required to determine the sex of embryos. 4. The rate of demi-embryos developed to blastocyst was 73.3% in TCM 199 medium supplemented with 0.1% solcoceryl. but 55.6% in control.

• Korean Journal of Animal Reproduction
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• v.24 no.3
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• pp.299-309
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• 2000

This study was performed 1) to establish the optimal PCR condition of sex determination in Hanwoo IVM/IVF embryos, 2) to examine the sex determination and sex ratio to the developmental stages of Hanwoo IVM/IVF embryos by two-step PCR method. The sexing of bovine IVF embryos were accurately determined by PCR methods using Y chromosome specific DNA primer(BOV 97M, 141bp) and bovine specific DNA primer(216bp). The fregment size were shown at 141 and 216 base pairs(bp) in male, and 216 bp in female. Two-steps PCR method in which the samples were amplified by 15 cycles with Y chromosome specific DNA primer and then amplified by additional 30 cycles with bovine specific DNA primer was effective in the sexing of bovine IVF embryos. The zona-free embryos were more effective than zona-intact embryos in bovine IVF embryo sexing. The appearance of Y chromosome specific band was 45.2% in embryos treated with protease K and 53.3% in embryos treated with freezing and thawing repeatedly. The optimun volume of DNA for sexing of Hanwoo IVF embryos were 2 to 10 $\mu$1 in Zona-free embryos and 12 to 13 $\mu$1 in zona-intact embryos. The sexing rate of bovine IVF embryos by PCR was 96.0% and questionable rate not identified sex was 4.0%, respectively. Among the sexed embryos, the percentage of male and female was 49.7% and 46.3%, respectively, the sex ratio was 1: 1.1. The successful rate of embryo sexing was increased to the developmental stages.

• Korean Journal of Animal Reproduction
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• v.20 no.4
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• pp.443-451
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• 1997

These studies were conducted to determine the sex of preimplantation Hanwoo embryos produced in vitro using polymerase chain reaction(PCR). Y chromosome specific and bovine speicific DNA primers were synthesized and tested for embryo sexing. Bovine IVF embryos were produced in TCM 199 and CR1aa medium, and classified by developmental stages on Day 7 to 9. The effects of developmental rates to bovine IVF blastocysts on sex ratio were also investigated using PCR methods. The results obtained in this study were as follows; 1. Developmental rates to blastocyst from IVM/IVF embryos in TCM 199 and CR1aa medium for 9 days were 23.5 and 30.2%, respectively, and there was significant difference between the media(P<0.05). 2. Male to female ratio of early, mid, expanded and hatching balstocyst produced on Day 7 were 0.7:1, 1.4:1, 2.2:1, and 2.5:1, respectively, and male embryos was significantly higher proportion in expanding and hatching blastocysts(P<0.01). 3. On Day 8, male to female ratio of early, mid, expanded and hatching blastocysts were 0.6:1, 1:1, 2.5:1, and 2.7:1, respectively. Both expanded and hatching blastocysts obtained a significantly higher proportion of males(P<0.01). 4. The male : female ratio of early, mid, expanded and hatching blastocyst produced on Day 9 was 0.6:1, 0.8:1, 1:1, and 2.2:1, respectively. Hatching blastocysts had a significantly higher ratio of males(P<0.01). The developmental rate of IVM/IVF embryos to blastocyst for 9 day culture was higher in CR1aa than that in TCM 199 medium. For the sex ratio by developmental stages of IVF embryos, male ratio was higher in expanded blastocyst but female in early blastocysts.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.10
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• pp.1411-1416
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• 2014

Gender selection is important in livestock industries; for example, female calves are required in the dairy industry. Sex-sorted semen is commonly used for the production of calves of the desired gender. However, assessment of the sex ratio of the sorted semen is tedious and expensive. In this study, a rapid, cost effective and reliable method for determining the sex ratio was developed using a multiplex real-time polymerase chain reaction (PCR) assay. In this assay, the X and Y chromosome-specific markers, i.e., bovine proteolipid protein (PLP) gene and sex-determining region Y (SRY) were simultaneously quantified in a single tube. The multiplex real-time PCR assay was shown to have high amplification efficiencies (97% to 99%) comparable to the separated-tube simplex real-time PCR assay. The results obtained from both assays were not significantly different (p>0.05). The multiplex assay was validated using reference DNA of known X ratio (10%, 50%, and 90%) as templates. The measured %X in semen samples were the same within 95% confidence intervals as the expected values, i.e., >90% in X-sorted semen, <10% in Y-sorted semen and close to 50% in the unsorted semen. The multiplex real-time PCR assay as shown in this study can thus be used to assess purity of sex-sorted semen.