ISSN:1424-8581    

DOI:10.1159/000134135

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

β-Catenin is one of the E-cadherin associated proteins involved in the process of cellular adhesion. It has recently been shown to interact with the APC protein whose gene is known to be mutated in the germline of familial adenomatous polyposis patients. This interaction implies that β-catenin is a potential regulator of the APC gene. The localization of the human β-catenin gene (CTNNB1) to chromosome 3p22, by fluorescent in situ hybridization (FISH), has linked the gene to a region that is frequently altered in several human malignancies. The location of the gene and the protein interactions suggest the importance of β-catenin in the etiology of various human canc

ISSN:1424-8581    

DOI:10.1159/000134136

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

By means of cloning, sequencing, and fluorescence in situ hybridization, we have determined that the EcoRI satellite DNA family is conserved in the 10 sparid species analyzed here. Its conservation, its chromosomal location at the centromere of each chromosome, and its structural features could make this satellite DNA family an important structural and/or functional element of the centromeres of these species. Monomeric units of this satellite DNA have a consensus length of 187 bp. Its sequence is characterized by a high AT content and the presence of short runs of consecutive AT base pairs. These monomeric EcoRl repeats also contain three to four copies, depending on the species, of a short sequence reflecting the repetitive duplication and subsequent divergence of an ancestral 9-bp sequence in this family. This sequence motive is conserved in some parts of the monomeric units of the different species studied at the same positions, and, precisely, surrounding the area in which the curvature of the monomeric molecule is greatest. The 9-bp sequence motive is similar to other direct-repeat sequences of the centromeric satellite DNAs of other vertebrates, including those of amphibians and mammals.

ISSN:1424-8581    

DOI:10.1159/000134137

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

We have cloned and sequenced the cDNA of a novel gene from the rat protamine gene cluster. This gene, preliminarily referred to as Prm3, is intronless and resides between the genes for protamine 2 and transition protein 2. Prm3 is transcribed from the same strand as these genes and is expressed in haploid stages of spermatogenesis. The 410-bp-long cDNA possesses an ORF, coding for a putative 104-amino acid polypeptide with a high content of glutamic acid.

ISSN:1424-8581    

DOI:10.1159/000134138

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Fifty-seven individuals of the European cyprinid fish species Scardinius erythrophthalmus were sexed by gonad histology, and their karyotypes were analyzed by Giemsa staining and C-banding. The chromosome number in somatic meta-phase plates was 2n = 50. Karyotypes of all gonadal male animals were identical, consisting of 48 small meta- or submetacentric chromosomes and a pair of large metacentric chromosomes (ZZ males). Of the 33 gonadal females, 16 had a karyotype similar to the males’ (ZW females) and 17 had a heteromorhic pair of chromosomes, including a large metacentric Z chromosome and a small acrocentric W chromosome (ZW females). H-Y antigen typing with cells obtained from a variety of tissues revealed that the homogametic ZZ males were H-Y negative and the heterogametic ZW females were H-Y positive in all tissues tested. In contrast, ZW’ females showed no expression of the H-Y antigen in somatic cells but were H-Y positive in ovarian cells. These results suggest that the ZW/ZW7ZZ sex chromosomes of S. erythrophthalmus represent an unusual system of sex determination and that H-Y antigen expression is coupled with the heterogametic sex. Whether the ZW individuals are indeed heterogametic females or actually sex-reversed ZZ males, in which chromosomal sex determination is overruled by external factors, is discus

ISSN:1424-8581    

DOI:10.1159/000134139

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The determination of geographic chromosomal variation in rare or endangered species, or those of special management concern, is important, since geographically defined cytotypes can negatively influence breeding programs involving founders drawn from widely divergent localities. We cytogenetically analyzed specimens of the roan (Hippotragus equinus) and sable antelope (H. niger) collected from widely divergent localities throughout their respective ranges. Each species was characterized by a diploid number of 60 and an invariant karyotype. In contrast to the absence of intraspecific variation, however, the two species differ with respect to centromeric constitutive heterochromatin and numbers of nucleolar organizer regions. These cytogenetic landmarks were subsequently used to verify an anecdotal account of a naturally occurring roan × sable hybrid. The data show that, despite their markedly distinct phenotypes, the roan and sable antelope are nonetheless sufficiently similar genetically to produce viable offspring. Hybridization, although a rare event between these species, is probably partly promoted by behavioral differences which are not always sufficient to prevent mating between them

ISSN:1424-8581    

DOI:10.1159/000134140

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Flow-sorted chromosome 18 material from the pig (SSC18) was amplified with SINE-PCR to generate DNA for molecular cloning. An SSC18-enriched library was constructed and subsequently screened with a (CA)15 probe to identify polymorphic microsatellites. Eleven unique micro-satellites were obtained, six of which constituted direct extensions of SINE poly(A) tracts. Eight primer pairs amplified polymorphic loci in unrelated pigs. The polymorphic markers were typed in a Swedish reference pedigree for porcine genome mapping, but only two of them (SO177 and SO179) mapped to SSC18. The remaining markers mapped to chromosomes 3, 4, 7, 9, and 11. Together with two markers from other sources (S0062 and sw787), a four-point linkage group on SSC18 could be established.

ISSN:1424-8581    

DOI:10.1159/000134141

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Using a panel of human-rodent somatic cell hybrids, we have previously mapped the gene (HPD, previously called PPD) encoding 4-hydroxyphenylpyruvate dioxygenase to the distal half of the long arm of human chromosome 12, region q14→qter. To obtain a genomic probe useful for fluorescence in situ hybridization (FISH) analysis we screened a human leukocyte genomic library and isolated a 13.4-kb phage clone, which by restriction fragment and sequence analyses was shown to contain exons 1–10 of HPD and approximately 2-kb upstream sequences. We now report the subregional localization of HPD to 12q24→qter based on two color FISH analysis employing this

ISSN:1424-8581    

DOI:10.1159/000134142

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

A cosmid clone containing the glucose transporter gene (SLC2A1) was selected from a cosmid library of swine genomic fragments by colony hybridization using the cDNA of swine glucose transporter as a probe. The genomic fragment thus cloned was partially sequenced, and the sequence was compared first with the sequence of the cDNA and then with the reported rat genomic sequence. The sequence homology and exon/intron structure indicated that the genomic fragment contained at least part of SLC2A1. The fragment, together with vector DNA, was then labeled by biotin and used as a probe for in situ hybridization on swine chromosome spreads. Hybridization was visualized by the FITC-labeled streptavidin/biotinylated anti-streptavidin system together with the R-band pattern of chromosomes. The fluorescence signals revealed that SLC2A1 is localized on swine chromosome 6q34→qte

ISSN:1424-8581    

DOI:10.1159/000134143

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Chromosome segregation and interchromosomal effects of reciprocal translocations at first meiotic division were investigated by chromosome analysis of meiotic cells from male Chinese hamsters heterozygous for two reciprocal translocations. We used six stocks heterozygous for two different translocations which were obtained by crosses between males and females homozygous or heterozygous for a different translocation. The frequency of second meiotic (MIl) cells from each segregational class of one quadrivalent in heterozygotes for two reciprocal translocations agreed with that of the same quadrivalent in heterozygotes for the single translocation. This indicates that the two quadrivalents in heterozygotes for two reciprocal translocations segregate independently. The mean frequency of hyperhaploid MIl cells from males heterozygous for two reciprocal translocations ranged from 7.1 to 15.4%. These cells were mostly derivatives from 3:1 disjunctions of the quadrivalents. The percentage of cells with extra chromosomes in translocation-unrelated groups was calculated at 0.10–0.25%. The frequency did not increase significantly as compared with that in karyotypically normal males, in which the mean frequency of hyperhaploid MIl cells was 0.39%. These findings revealed that reciprocal translocations do not have interchromosomal effects on meiotic division in male Chinese hamster

ISSN:1424-8581    

DOI:10.1159/000134144

出版商:S. Karger AG    

年代:1995

数据来源: Karger