Frequency of chromosomal abnormalities in embryos from superovulated Merino ewes

Murray, John E.; Boland, M.P.; Moran, Chelsea

doi:10.1530/jrf.0.0780433

Cited by 11 publications

(7 citation statements)

References 16 publications

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“…After measurement, all embryos were cultured in a solution of colchicine and processed for chromosome analysis (Murray et al, 1985(Murray et al, , 1986a). The chromosome data from the day 2 embryos have been reported separately (Murray et al, 1988).…”

Section: Measurement Of Embryos and Blastocystsmentioning

confidence: 99%

Reproductive wastage in the androstenedione-immune ewe

Scaramuzzi¹,

Nancarrow²,

Murray³

et al. 1993

Reproduction

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An experiment was carried out using 320 adult Merino ewes to examine the effects of immunization against an androstenedione human serum albumin conjugate (Fecundin) on ovulation rate, fertilization rate and embryo viability at days 2, 9 and 13-14 after fertilization. The ovulation rate of immunized ewes (2.19 +/- 0.06) was greater (P < 0.001) than that of control ewes (1.43 +/- 0.04). The recovery rate of embryos or of unfertilized oocytes on day 2 was reduced in immunized ewes, but fertilization rate of recovered oocytes was unaffected by immunization. The mean number of normal embryos per ewe pregnant (prolificacy) was higher and the proportion of ewes pregnant (fertility) was lower in immunized than in the control ewes. The distribution of the number of cells per embryo showed no differences in developmental age over the period of sampling, the majority of embryos at this time being at the two- to four-cell stage of development. At day 9 of pregnancy, blastocyst recovery rates were lower in immunized than in control ewes. About 90% of blastocysts recovered were developing normally in control ewes compared with 64% in immunized ewes. The majority of blastocysts recovered on day 9 had hatched from the zona pellucida prior to recovery (mean values were 94.2% and 87.8% for control and immunized groups, respectively). In control ewes single blastocysts were larger than twin blastocysts, but for the immunized ewes this difference was not significant. Both single blastocysts (P < 0.01) and twin blastocysts (P < 0.05) from immunized ewes were smaller than those from control ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Measurement Of Embryos and Blastocystsmentioning

confidence: 99%

Reproductive wastage in the androstenedione-immune ewe

Scaramuzzi¹,

Nancarrow²,

Murray³

et al. 1993

Reproduction

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“…Until now, total haploidy has not been reported in day-7 bovine embryos developed in vivo. However, in bovine embryos matured, fertilized and developed in vitro (Iwasaki et al, 1989) and in porcine (Van der Hoeven et al, 1985) and ovine (Murray et al, 1986b) embryos developed in vivo, a low inci¬ dence of total haploidy has also been observed. Conversely, in human (Angeli et al, 1983) and murine (Whittingham, 1980;Kaufman, 1985;Surani et al, 1987) embryos, complete haploidy, which is thought to be the result of the parthenogenetic activation of the oocyte, occurs more frequently.…”

Section: Discussionmentioning

confidence: 99%

“…Of the chromosome abnormalities that have been found in embryos, mixoploidy (for example diploidy-haploidy, diploidy-triploidy) is the most commonly observed (Kind, 1990). Mixoploidy has been found more often in embryos that were morphologically abnormal than in embryos that were morphologically normal (King et al, 1987(King et al, , 1988 in cows. Gonadotrophins, which are used for superovulation, may increase (Long and Williams, 1980) or decrease (Murray et al, 1986b) the frequency of these aberrations. In addition, culturing the embryos may increase the number of polyploid cells (Barlow and Sherman, 1972; Johnson and Rossant, 1981).…”

Section: Introductionmentioning

confidence: 99%

Cytogenetic analysis of day-7 bovine embryos by cytophotometric DNA measurements

Dorland

Duijndam²,

Kruip³

et al. 1993

Reproduction

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A Feulgen staining procedure that stains the DNA of individual fixed nuclei stoichiometrically was used to analyse cytophotometrically the incidence of total ploidy and mixoploidy in 28 day-7 bovine embryos that had been fixed after collection ('non-cultured' embryos). The influence of culture on the incidence of chromosome abnormalities was further studied in another group of 24 embryos ('cultured' embryos) by culturing them for 24 h in Whittingham's medium. Of the total 52 embryos studied, two appeared to be entirely abnormal: one embryo was completely haploid, whereas the other embryo was completely triploid. Individual hyperdiploid nuclei and hypodiploid nuclei were frequently observed in the otherwise diploid embryos. As haploid polar bodies can still be present in morulae and blastocysts (to a maximum of three), only embryos with more than three hypodiploid nuclei were considered as abnormal. Of the 'non-cultured' embryos, 33.3% had one or more hyperdiploid nuclei, whereas 51.9% had more than three hypodiploid nuclei. In this latter group, 35.7% of the embryos also had hyperdiploid nuclei. The results also showed that day-7 bovine embryos that are completely haploid, completely triploid or mixoploid cannot be detected only by examining their morphology. It is concluded that the incidence of, especially, mixoploidy in embryos can be better studied by measuring the DNA content of the individual nuclei of an embryo rather than by analysing chromosomes, as in the latter method only dividing cells can be analysed. The presence of hyperdiploid and hypodiploid nuclei may indicate the frequent occurrence of mitotic segregation failures during mitosis in bovine embryos.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Most of the abnormal embryos are lost by day 13 of development in the Merino, as Murray et al (1986b) observed chromosome abnormalities in only 1·9% of the elongated blastocysts examined. This is also consistent with other work where the incidence of chromosome abnormalities was very low in blastocysts of sheep (Long 1977) and cattle (Hare et af.…”

Section: -"mentioning

confidence: 93%

“…There are no data available on the frequency of chromosome abnormalities in cleavage-stage embryos from pigs, and the data available for cattle are confounded by the use of exogenous hormones to produce superovulation (King et al 1981;Gayerie de Abreu et al 1984;Murray et al 1985b). The possible effects of superovulation on the incidence of cytogenetically unbalanced embryos is not clear, as conflicting evidence has been published from both livestock and laboratory species (see Murray et al 1986b).…”

Section: Introductionmentioning

confidence: 99%

Polyploid Abnormalities in Day 3 and Day 5 Merino Sheep Embryos

Murray

Nancarrow²,

Scaramuzzi³

et al. 1988

Aust. Jnl. Of Bio. Sci.

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The chromosome complement was assessed in Merino sheep embryos collected at 3 and 5 days after the onset of oestrus. Donor ewe treatments were: untreated, or immunized against androstenedione (day 3); and untreated, or treated with follicle-stimulating hormone (FSH), or treated with FSH plus immunization against androstenedione (day 5). No significant differences in the frequency of chromosomally abnormal embryos between treatment groups within each age group were observed, so the data have been combined.Euploid abnormalities were observed in 10·8070 of the day-3 embryos (4/37), with the abnormalities being one In, one 3n and two 5n. Embryos with euploidy (10%) were also observed at day 5, with three 1n12n mosaics and a 3n embryo present in a sample of 40. These data suggest that chromosomally aberrant embryos are not lost before day 5 of development.

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Frequency of chromosomal abnormalities in embryos from superovulated Merino ewes

Cited by 11 publications

References 16 publications

Reproductive wastage in the androstenedione-immune ewe

Reproductive wastage in the androstenedione-immune ewe

Cytogenetic analysis of day-7 bovine embryos by cytophotometric DNA measurements

Polyploid Abnormalities in Day 3 and Day 5 Merino Sheep Embryos

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