Selective elimination of chromosomally unbalanced zygotes at the two-cell stage in the Chinese hamster

Sonta, Shin-ichi; Fukui, K; Yamamura, Hideki

doi:10.1159/000132022

Cited by 31 publications

(20 citation statements)

References 10 publications

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“…The frequency of each disjunctional class was estimated by the MII counts in male and female translocation heterozygotes. The frequency of each disjunctional class was similar among males heterozygous for the same reciprocal translocation (Sonta et al, 1984). Among males and females heterozygous for the same translocation, there is no difference in the frequency of each disjunctional class (Table 3).…”

Section: Chromosomal Segregation In Translocation Heterozygotesmentioning

confidence: 85%

“…Preparations of secondary spermatocytes were made by the method of Evans et al (1964). From females, preparations of secondary oocytes were made according to the method of Kamiguchi et al (1976), with slight modifications (Sonta et al, 1984).…”

Section: Chromosomal Segregation In Translocation Heterozygotesmentioning

confidence: 99%

“…More than 500 sperm were analyzed in male heterozygotes in each strain. 0.04 pg/ml colcemid, 0.005 pg/ml vinblastine, and 0.004 pg/ml podophyllotoxin (Sonta et al, 1984). The methods for chromosome preparations of fertilized ova were the same as for MII oocytes, with slight modifications.…”

Section: Participation Of Chromosomally Unbalanced Gametes In Fertilimentioning

confidence: 99%

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Contribution of chromosomal imbalance to sperm selection and pre-implantation loss in translocation-heterozygous Chinese hamsters

Sonta

2004

Cytogenet Genome Res

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Chinese hamster stocks with various structurally abnormal chromosomes have been produced by X irradiation. Among these stocks, 18 with various reciprocal translocations were used to investigate the participation of unbalanced gametes in fertilization and the development of unbalanced embryos. Among males as well as females heterozygous for the same translocation, there is no difference in the frequency of each disjunctional class. The participation of chromosomally unbalanced gametes in fertilization was investigated by chromosomal analysis of meiotic cells in heterozygotes for the 18 reciprocal translocations and pronuclei of fertilized ova obtained from crossing these heterozygotes. Compared with the expected frequencies from MII scoring, the frequencies of male pronuclei having a common deficiency of chromosome 1 (1q17→1q42) or chromosome 3 (3p23→3q31) decreased significantly in one-cell embryos. However, the frequencies of male pronuclei with other abnormalities were all consistent with those expected from MII scoring. In contrast, the frequencies of female pronuclei with any karyotype including the same abnormalities as those decreased in male pronuclei from the translocation heterozygotes were all consistent with those estimated from MII scoring. These results revealed clearly that most gametes with nullisomies as well as disomies for any chromosomal segments may participate in fertilization, whereas only male gametes nullisomic for certain segments of chromosomes 1 and 3 failed to participate in fertilization. The zygotic selection of chromosomal imbalance was also investigated by direct chromosomal and morphological analyses of preimplantation embryos from crosses between karyotypically normal females and male heterozygotes from the 18 stocks with various reciprocal translocations. These analyses revealed that some embryos were arrested in development at the two-cell stage. The karyotype of these two-cell embryos had a common deficiency in a segment of chromosome 1 or chromosome 2. Embryos with partial monosomy including chromosomes 1, 3, 4 and 5 showed arrested development at four- to eight-cell stages. Among day 4 embryos, some chromosomally unbalanced embryos, mainly with a deficiency of segments of chromosomes 1p, 1q, 2q, 5q, 7q and 8, had fewer blastomeres than karyotypically normal and balanced embryos. The homology between Chinese hamster and mouse chromosomes relating to abnormal embryogenesis at early stages has been partially confirmed from reported maps of chromosomes. The Chinese hamster is useful for further cytogenetic studies during the stages of meiosis and early embryogenesis.

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Section: Chromosomal Segregation In Translocation Heterozygotesmentioning

confidence: 85%

Section: Chromosomal Segregation In Translocation Heterozygotesmentioning

confidence: 99%

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Contribution of chromosomal imbalance to sperm selection and pre-implantation loss in translocation-heterozygous Chinese hamsters

Sonta

2004

Cytogenet Genome Res

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“…Primary cultures of fibroblastic cells were obtained from the lung or tail tip of two female Chinese hamsters heterozygous for a reciprocal translocation of either T(2 ; 3) lIdr or T(2; 10) 3Idr (Sonta and Oishi 1982;Sonta et al 1984). The two types of translocations were identified in the primary cultures as t(2 ; 3) (q24 ; p13) and t(2 ;10) (q18 ; ql l) respectively, according to the standard nomenclature (Ray and Mohandas 1976), which gave rise to four types of derivative chromosomes containing different segments of chromosome 2 as illustrated in Fig.…”

Section: Methodsmentioning

confidence: 99%

Regional assignment of ENO1, PGD, and PGM1 to the long arm of Chinese hamster chromosome 2.

Satoh

Sonta²,

Yoshida

1985

The Japanese journal of genetics

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The loci for ENO1, PGD, and PGM1 were regionally assigned to Chinese hamster chromosome 2 using mouse x Chinese hamster somatic cell hybrid clones containing rearranged hamster chromosomes derived from T(2 ; 3) lIdr and T(2;10)3Idr translocation stocks of the Chinese hamster. Segregation analysis of the rearranged hamster chromosomes and expression of marker enzymes indicated that these genes are located on the region 2g24-*2gter. Combining the present results with those in the literature, we confirmed the previous assignment of ENO1 and PGD loci to 2g33-*2gter, and narrowed the localization of PGM1 from 2g23-~2g33 to 2g24-±2g33.

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“…By direct chromosome analysis of the second meiotic (MII) cells, we investigated chromosome segregation in heterozygotes for various reciprocal translocations in the Chinese hamster (Sonta et al, 1984(Sonta et al, , 1991b. Among individuals heterozygous for unequal reciprocal exchanges, marker chromosomes with chromatids of unequal length are seen in MII cells as a result of crossing-over on the "interstitial" segments of translocation chromosomes (Fig.…”

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confidence: 99%

Origin of the adjacent 1 disjunction

Sonta

1993

Jap J Human Genet

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To investigate individuals heterozygous for reciprocal translocations is one object of prenatal diagnosis because of the high risks inherent in chromosomally unbalanced offspring (Bou6 and Gallano, 1984;Daniel et al., 1988). In genetic counseling, it is important to estimate the percentage risk of having such offspring (Fuhrmann and Vogel, 1982;Harper, 1988)~ The risks may depend on events including various ratios of cells with an unbalanced chromosome constitution resulting from segregation from quadrivalents, the lack of unbalanced gamete participation in fertilization, and selection of unbalanced embryos during the period from early embryogenesis to later development.Segregation ratios from quadrivalents in tanslocation heterozygotes have often been discussed on the basis of cytogenetic data from offspring and fetuses of translocation carriers (Petrosky and Borgankar, 1984;Stene and Stengel-Rutkowski, 1988). The chromosome segregation in male translocation heterozygotes has also been studied by sperm chromosome analysis using the hamster oocyte-human sperm fusion technique (Martin, 1988; Spriggs et aI., 1992). Several authors have described that, when the genotype of offspring and sperm are normal or balanced, the gamete derived from alternate disjunction in the translocation heterozygote. When the genotype is unbalanced, on the other hand, they assume that the gamete originated from the adjacent 1, 2, or 3:1 disjunction. In this really the case?In studies of offspring or sperm in translocation heterozygotes, however, no one has obtained data of meiotic crossing-over, except in a few individuals with specific karyotypes from adjacent 2 and 3:1 disjunctions accompanying crossingover, which are usually rare (Lindenbaum, 1990;Spriggs et al., 1992). A meiotic crossing-over can not usually be detected as a specific change of the karyotype in gametes and zygotes. In particular, when the alternate disjunction occurs accompanying meiotic crossing-over at the "interstitial" (in this letter, a segment between the centromere and a break point in a derivative chromosome) segment in translocation heterozygotes, the derived karyotypes seen in gametes and zygotes might be indistinguishable from those derived from the adjacent 1 disjunction accompany-

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Selective elimination of chromosomally unbalanced zygotes at the two-cell stage in the Chinese hamster

Cited by 31 publications

References 10 publications

Contribution of chromosomal imbalance to sperm selection and pre-implantation loss in translocation-heterozygous Chinese hamsters

Contribution of chromosomal imbalance to sperm selection and pre-implantation loss in translocation-heterozygous Chinese hamsters

Regional assignment of ENO1, PGD, and PGM1 to the long arm of Chinese hamster chromosome 2.

Origin of the adjacent 1 disjunction

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