摘要:

As part of our ongoing linkage studies of degenerative retinal diseases, we tested seven DNA markers and two classical genetic markers from chromosome 4 in two extended families with autosomal dominant retinitis pigmentosa (ADRP). Our goals were (1) to detect or exclude linkage of ADRP to markers spanning most of chromosome 4 and (2) to contribute useful new information regarding the linkage map of this chromosome. Our results exclude linkage of ADRP from more than 82% of chro mosome 4. We detected four new linkage relationships: loose linkage of K082 (D4S10) and G1E5 (D4S21) at a distance of 21 cM; loose linkage of 4F2 (D4S18) and GC protein at a distance of 19 cM; tight linkage (i.e., no recombinants) between B3D (D4S44), B5A (D4S40), and the MNS blood group; and tight linkage between 4F2 and GDS5 (D4S23). These data, combined with previously reported data, exclude ADRP from approximately 35% of the human genome.

ISSN:1424-8581    

DOI:10.1159/000132758

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

In a litter of nine domestic pigs, a translocation between the X-chromosome and chromosome 13 was found in six individuals: four males and two females. The translocation was presumed to have originated in the dam. Banding studies indicated that the breaks preceding the translocation had occurred in a distal GTG-negative band of the long arm of the X, 15–30% of the length of Xq from thetelomere, and proximally in chromosome 13, 15–25% from the centromere. The normal X of the females invariably replicated its DNA late. Synaptonemal complex analysis of spermatocytes demonstrated a quadrivalent in 75 of 85 analyzable cells (88.2%), and in 10 cells (11.8%) one trivalent and one univalent were found. Extensive nonhomologous pairings were visualized in the pachytene stage by applying an ‘overlap’ test measuring the sex chromosomes and collating their pairings. An arrest in male meiosis was verified histologically; no meiotic stages later than pachytene developed. This resulted in sterility, with considerable testicular hypoplasia. The records of female fertility were available only for the dam and did not show any deviations from the average of t

ISSN:1424-8581    

DOI:10.1159/000132772

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Using four repetitive sequences, we compared DNAs isolated from Mus caroli, M. cookii, M. hortulanus, M. musculus, M. pahari, M. saxicola, and M. spretus. Except for Bl, these probes showed species-specific hybridization patterns. Mouse interspersed fragment (MIF) sequences were present in all species examined, but those defined by the 1.3-kb EcoRl band were fewer in M. pahari and M. saxicola than in the other species. The Y-chromosomal probe showed male-specific accumulation only in M. hortulanus, M. musculus, and M. spretus, which are known to be closely related. The genetic difference between M. spretus and the other two species (M. hortulanus and M. musculus) was clearly demonstrated by a M. musuclus centromeric sequence that hybridized strongly to M. hortulanus and M. musculus DNA but was underrepresented in the genome of M. spretus. These results may suggest the usefulness of these repetitive sequences in the classification of Mus species that display only subtle morphological differences.

ISSN:1424-8581    

DOI:10.1159/000132759

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

In a representative sample of primate species, including simians (Catarrhini and Platyrrhini) and prosimians (Lemuriformes and Lorisiformes), high-resolution, early replication banding revealed a homoeologous early replicating segment at the ends of both sex chromosomes. The DXYZ2 element, a repeated sequence specific for the human pseudoautosomal region, is con served in the genomes of all primate species studied and is specifically localized in the distal early replicating segments of the X and Y chromosomes. Thus, cytogenetic and molecular evidence is presented of a highly conserved sex-chromosomal segment in primates. The pseudoautosomal behavior of this segment is discussed.

ISSN:1424-8581    

DOI:10.1159/000132760

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

A probable role of heterochromatin variation in male meiosis has been evaluated using fertile and infertile Indian mole rat males (Nesokia) with polymorphic X and/or Y chromosomes. A comprehensive study of tubular histology, meiotic progression, and X-Y chromosome pairing was undertaken. Despite heterochromatin variation, spermatogenesis was found to be complete in all individuals. Patterns of X-Y synaptonemal complex pairing varied considerably from extensive synapsis in individuals with a normal heterochromatin complement, through end-to-end synapsis, to X and Y univalents in those with different degrees of loss of heterochromatin. Changes in the gonadal histology corresponding to heterochromatin variation were also observed. Loss of some coding DNA sequences in polymorphic X-chromosomes otherwise located at specific sites in the X-chromosome heterochromatin have been linked directly to modifications of the reproductive process. This is thought to be mediated by an altered X-chromosome activity during spermatogenesis or regulation of other locus/loci involved in fertility or reproduction.

ISSN:1424-8581    

DOI:10.1159/000132761

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

We report the construction of eight human chromosome-specific DNA libraries. Metaphase chromosomes were purified by flow-sorting, and the extracted DNA was cleaved with HindIII before cloning into λCharon 21 A. There is now a complete digest HindIII library containing greater than five chromosome equivalents for each human chromosome. These are available to the scientific community through the American Type Culture Collection in Rockville, MD. The amount of hamster DNA in libraries in which the chromosome was sorted from human × hamster hybrid cells was estimated by species-specific hybridization. It ranged from 5% to 39%. The sorted chromosomes were examined by fluorescence in situ hybridization with species-specific DNA, and the main source of the hamster DNA contamination was found to be intact hamster chromosomes. In addition, we examined a chromosome 21 library, LL21NS02, for clones that fail to grow on the rec+ host LE392. Less than 0.6% of the recombinant phage exhibited the rec+-inhibited phenotyp

ISSN:1424-8581    

DOI:10.1159/000132762

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The gene for hereditary hemochromatosis is linked to the HLA locus on chromosome 6. Four cloned DNA probes originating from the HLA class I region were used to detect seven restriction fragment length polymorphisms (RFLPs). Allele frequencies and segregation of each RFLP was determined. Analysis of RFLPs in 38 unrelated homozygotes with hemochromatosis revealed differences in allele frequencies between the control and the hemochromatotic groups but these differences did not reach statistical significance. Some differences persisted, however, even when only controls with the A3 antigen were compared with A3 hemochromatotics. Since both control and hemochromatotic groups were small, further studies will be necessary to ascertain whether these RFLPs could serve to locate the gene responsible for hereditary hemochromatosis.

ISSN:1424-8581    

DOI:10.1159/000132763

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

An electron microscopic study of synaptonemal complexes in two heterozygous fertile boars, one a carrier of a 4; 14 reciprocal translocation and the second a carrier of this translocation associated with a 3;7 reciprocal translocation, is reported. The results showed heterologous pairing in almost all quadrivalents, as well as a lack of XY-quadrivalent association. This seemed to be a common feature of translocations in pigs, even if at least one acrocentric chromosome is involved, and may represent a significant meiotic mechanism that prevents spermatocyte loss, while the production of genetically unbalanced gametes leads to loss of progeny through abortion.

ISSN:1424-8581    

DOI:10.1159/000132764

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Deletions in the long arm of chromosome 7 are common recurrent abnormalities in secondary leukemias and myelodysplastic syndromes. To learn more about the basic mechanisms involved, we used Southern blot analysis to study four patients with different 7q — deletions to determine the exact breakpoints and to define the extent of the deletions. Several genes and DNA sequences from 16 different loci were found to be deleted, as judged by the absence or considerable weakening of an allelic band in granulocytic DNA in patients with constitutional heterozygosity. A terminal segment was present in each of the partially deleted chromosomes, as shown by heterozygosity for probes from the region 7q35→qter in granulocyte DNA. This indicated that the chromosome 7q deletions were interstitial, rather than terminal, in each of these patients. The length of the preserved terminal segment varied among the patients. Our results support gene loss as a mechanism contributing to leukemogenesis. Since the deletions are interstitial, hybrid genes may be formed at the junction, but the variation in breakpoints argues against the existence of a common hybrid gene of importance to the malignant proc

ISSN:1424-8581    

DOI:10.1159/000132765

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

We have established a new Epstein-Barr virus transformed cell line from a patient with B-cell follicular lymphoma. Telomeric fusions were observed in several subclones, with the nonrandom involvement of chromosomes 1, 5, 12, and 17. Centromeric staining with immunofluorescent anti-kinetochore antibodies was positive in both centromeres of the fused chromosomes, suggesting they were both active. Unlike previously reported cases, we were unable to demonstrate telomeric fusions directly in cells from the patient’s blood. However, the finding of identical immunoglobulin gene rearrangements in DNA from the patient’s blood and cell line suggested that they originated from the same malignant B-cell cl

ISSN:1424-8581    

DOI:10.1159/000132766

出版商:S. Karger AG    

年代:1989

数据来源: Karger