摘要:

Polyspermy occurs with a frequency of about 12% under some hormonal regimens currently being used for in vitro fertilization and embryo transfer. Oocytes with three pronuclei usually show normal cleavage and are morphologically indistinguishable from embryos produced by normal fertilization. Chromosome studies and DNA measurements on dispermic embryos show that about one-half are triploid, the others having either a normal diploid chromosome complement or a severely depleted chromosome complement. The evidence suggests that these errors must arise at the first mitotic division of the oocyte. Aberrant spindle formation is implicated.

ISSN:1424-8581    

DOI:10.1159/000132242

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

The XY sex-reversal syndrome occurs when a phenotypic mare is born that has the karyotype of a stallion. The syndrome is manifested by both genotypic and phenotypic heterogeneity. The sex-reversed genetic condition occurs frequently within certain pedigrees where XY females have been found and can be readily detected by chromosome karyotyping. The phenotypic spectrum ranges from the feminine mare with a reproductive tract that is within normal limits to the greatly masculinized mare. Pedigree analysis suggests that there are two modes of inheritance: (1) an X-linked recessive or autosomal sex-limited dominant transmitted through the female and (2) an autosomal sex-limited dominant or a Y chromosomal mutation with variable expression transmitted through the male.

ISSN:1424-8581    

DOI:10.1159/000132243

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

MDH2, SOD2, PEPS, and ITPA were assigned to Papio papio chromosomes 3, 4, 5, and 10, respectively, by their concordant segregation with previously assigned gene markers in a set of baboon × mouse somatic cell hybrids. The linkage of NP, IDH2, SORD, MP1, and PKM2 was confirmed, and three other independently segregating markers (MDH1, ACY1, and PEPB) were identified. Syntenic groups described in the baboon are compared to those found in man and in the rhesus monkey

ISSN:1424-8581    

DOI:10.1159/000132244

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

Tissue plasminogen activator is one of the two plasminogen activators, both serine proteases, that catalyze the conversion of inactive plasminogen to plasmin, which then degrades the fibrin network of blood clots. By combining somatic cell genetics, in situ hybridization, and Southern blot hybridization, we localized the human tissue plasminogen activator gene to the pericentromeric region of chromosome 8.

ISSN:1424-8581    

DOI:10.1159/000132245

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

Phenylalanine hydroxylase (PAH) and tyrosine hydroxylase (TH) are consecutive enzymes in the metabolic pathway leading to the production of catecholamine neurotransmitters. A comparison of recently available sequence data of these enzymes in the rat indicates about 70% homology in the 3’ coding regions. We have localized TH by in situ hybridization to human chromosome region 11p15. Consideration of this assignment and that of PAH to chromosome 12, together with the known distribution of other pairs of related genes on these two chromosomes, provides convincing evidence of their ancestral relationship and suggests a role for gene duplication in the diversification of metabolic pathways in the vertebrate ancestors of mammal

ISSN:1424-8581    

DOI:10.1159/000132246

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

Circulating lymphocytes of many mammals, especially rodents, have proven refractory to PHA stimulation of mitotic activity. Addition of small amounts of lithium chloride to the culture medium removes the refractoriness and increases the yield of metaphase cells 7 fold. This simple procedure makes possible the routine use of circulating lymphocytes in rodent karyology.

ISSN:1424-8581    

DOI:10.1159/000132247

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

In situ hybridization of radiolabeled fibrinogen cDNAs to human and rat metaphase chromosomes has shown that the genes encoding the Aα, Bβ, and γ fibrinogen subunits are syntenic in both species. Our data localize the human fibrinogen gene cluster to band q31 on chromosome 4, thereby confirming and extending previous map assignments of these genes in man. We have also assigned these genes to the q31→q34 region of rat chromosome 2. This is the first map assignment of these genes in the rat and also the first report to clearly establish linkage of the Bβ subunit gene to the Aα and γ genes in this

ISSN:1424-8581    

DOI:10.1159/000132248

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

A sample of 437 reciprocal translocations was classified into three groups according to their method of ascertainment (Group I = couples with repeated abortions; Group II = karyotypically unbalanced carriers; Group III = balanced translocation heterozygotes). Statistical analysis showed that the distributions of chromosome breaks observed in the three groups could not be accounted for by chromosome arm length alone. In couples with repeated abortions, an excess of breaks in 7p, 17p, and 22q was found, whereas in the balanced translocation heterozygotes an excess of breaks was found only in 11q. An excess of breaks was found in arms 9p, 14p, 18p, 18q, 21q, and 22q in karyotypically unbalanced probands. A significant decrease of breaks in the medial chromosome regions was accompanied by a concomitant increase in the terminal regions in all groups. The three groups demonstrated different distributions of chromosome arm involvement in the observed translocations. Balanced translocation heterozygotes had the highest frequency of large (greater than the length of 4p) translocated segments and an excess in the frequency of large-large translocations, whereas karyotypically unbalanced probands had the highest frequency of small (shorter than 21q) translocations and an excess in the frequency of small-small translocations. For each type of chromosomal imbalance observed, the balanced translocation heterozygotes demonstrated the greatest potential imbalance and the karyotypically unbalanced probands the least.

ISSN:1424-8581    

DOI:10.1159/000132249

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

A sample of 229 Robertsonian translocations was classified into three groups according to the method of their ascertainment (Group I = couples with repeated abortions; Group II = karyotypically unbalanced probands; Group III = balanced translocation heterozygotes). Statistical analysis showed that the distributions of Robertsonian translocations differed significantly from random in all three groups. Additionally, the distributions were significantly different between couples with repeated abortions and karyotypically unbalanced probands and between unbalanced probands and balanced translocation heterozygotes.

ISSN:1424-8581    

DOI:10.1159/000132250

出版商:S. Karger AG    

年代:1986

数据来源: Karger

摘要:

A common cytogenetic finding in both Q-banded and solid Giemsa-stained preparations of pronuclear chromosomes obtained from cross-species fertilization of hamster oocytes by human sperm is the presence of a variable-length “gap” in the centromeric region. Scanning electron microscopy was used to investigate these altered chromosomal regions. The centromere in most eukaryotic organisms appears as a constricted region approximately 200–300 nm in diameter. In contrast, the gap portion of the centromeric region of pronuclear chromosomes was found to contain a chromatin fiber with a diameter of 80–150 nm. The detection of this fiber confirms that the chromosome arms are continuous, and the size of the fiber explains the gap appearance in the light photomicrographs. The morphology of the fiber is consistent with the concept that the normal chromatin packaging has been altered in varied regions within the centromere of these chro

ISSN:1424-8581    

DOI:10.1159/000132251

出版商:S. Karger AG    

年代:1986

数据来源: Karger