ISSN:1424-8581    

DOI:10.1159/000133449

出版商:S. Karger AG    

年代:1993

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000133450

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

We have used the fluorescence in situ hybridization (FISH) technique to refine the localization of the cystic fibrosis transmembrane conductance regulator (CFTR) gene on human chromosome 7. The result shows that the gene is most likely located within band q31.3.

ISSN:1424-8581    

DOI:10.1159/000133451

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Aphidicolin (APC)-sensitive fragile sites were identified in chromosome preparations from peripheral lymphocyte cultures of 12 four-way crossbred pigs. A χ2 analysis demonstrated that aphidicolin-induced breakage events and previously reported in vivochromosome rearrangement events were not independent. Comparison of expected Poisson and negative binomial distributions to observed breakage patterns indicated that the negative binomial distribution provided a better fit to experimental data. The negative binomial distribution is consistent with a distribution of breakage rates, i.e., non-constant rates of breakage at chromosomal loci across the genome

ISSN:1424-8581    

DOI:10.1159/000133452

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

This appears to be the first reported case of a bull with a balanced autosomal reciprocal translocation associated with azoospermia. The analysis includes somatic chromosome banding, conventional meiotic analysis, and electron microscopy of synaptonemal complexes (SCs). The karyotype of the bull was found to be 60, XY, rcp(8;13)(ql l;q24). Electron microscopy of SCs in microspread pachytene spermatocytes revealed a high incidence of terminal asynapsis of the smallest arm of the quadrivalent. Most quadrivalents with such asynapsis and few with nonhomologous synapsis showed associations with the XY sex bivalent, leading to complete meiotic arrest at late pachynema. Except for one diakinetic cell, no diplotene and subsequent stages were encountered in air-dried meiotic preparations. The presence of degenerating primary spermatocytes in SC preparations, as well as in testicular sections, and the absence of spermatozoa in ejaculates confirm the chromosomally derived male sterility of the bull. X-chromosome reactivation, evidenced by the cytomorphological reversal of associated sex bivalents, appeared to be the initial step in the degeneration of spermatocytes. Consequently, the formation of a separate, fully developed XY body, which was previously demonstrated on the periphery of spermatocyte nuclei in fertile bulls, could not be attained in this case. Extensive end-to-end association of autosomal bivalents in meiotically arrested, as well as degenerating, spermatocytes was a consistent and unique observation of this study. Such associations may lead to enhanced reactivation of the X chromosome.

ISSN:1424-8581    

DOI:10.1159/000133453

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

A reciprocal translocation was identified in a subfertile artificial insemination bull. Somatic chromosome investigation of G-banded metaphases demonstrated a 60, XY, rcp(20;24)(q17;q25) karyotype for the carrier. Synaptonemal complex analysis of the translocation by electron microscopy revealed an irregular pairing behavior of the chromosome axes involved, which resulted in a variety of configurations at pachytene. Not only was the expected quadrivalent configuration present, but also a trivalent plus univalent and two heteromorphic bivalents. Most common was an incompletely or completely paired quadrivalent configuration, which was non-homologously paired. XY association with the multivalent was seen only rarely. Histological analysis of testicular tissue showed meiotic arrest in some tubules. However, the semen picture was normal.

ISSN:1424-8581    

DOI:10.1159/000133454

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

We determined the precise genetic location of the human endothelin-1 gene (EDN1), which encodes a peptide with extremely potent vasoactive properties and is apparently involved in a spectrum of diseases ranging from hypertension to asthma. Analyzing the segregation of a four-allele EDN1 polymorphism in 40 CEPH families including 480 individuals, we detected significant linkage of EDN1 to DNA markers spanning the telomeric half of chromosome arm 6p. EDN1 was closest to the highly polymorphic nucleotide-repeat marker D6S89 at a theta = 0.06 with the highest pairwise LOD score Zmax = 31.2. Subsequent multipoint analysis placed EDN1 at 8 cM distal to D6S89; EDN1 was flanked at its telomeric site at a 13-cM distance by the gene encoding the A subunit of blood clotting factor XIII (F13A1). Furthermore, EDN1 was located at approximately 34–36 cM distal to the HLA region defined by HLA-A, -B, and -DRB1, and 31 cM proximal to the most telomeric marker D6S7. This location of EDN1 on the primary genetic map is strongly supported with odds of 2.7 × 1012:1 against the next best alternati

ISSN:1424-8581    

DOI:10.1159/000133455

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The α-globin gene complex in Equus caballus has been mapped by fluorescence in situ hybridization to the telomeric region of the long arm of chromosome 13. This is the first equine gene to be mapped to this chromosome

ISSN:1424-8581    

DOI:10.1159/000133456

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

We present here a new PCR-based technique that allows the production of several micrograms of DNA from only 300 flow-sorted chromosomes. During the first two PCR cycles, the annealing temperature is decreased to 30 °C, and numerous random loci are amplified under nonspecific conditions. As demonstrated here for pig chromosomes 1 and 18, the PCR products may be used to identify the chromosomal content of the flow-karyotype peaks of any species by fluorescence in situ hybridization

ISSN:1424-8581    

DOI:10.1159/000133457

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

Southern blotting, C-banding, base-specific fluorochrome staining, and fluorescence in situ hybridization were used to analyze the constitutive heterochromatin in eight species and subspecies of arvicolid rodents (genus Microtus). Autosomal centromeric regions portrayed considerable variability between species in the amount of C-band-positive material present; e.g., M. chrotorrhinus showed relatively little, whereas M. cabrerae exhibited extensive centromeric staining. Autoso-mal interstitial C-bands were noted in M. guentheri and two subspecies of M. ochrogaster. All Y chromosomes examined were predominately or completely heterochromatic, as were substantial portions of the giant X chromosomes in three species (M. agrestis, M. cabrerae, and M. chrotorrhinus). Hoechst 33258 staining (with its affinity for AT binding sites) showed bright fluorescence on the heterochromatin of the sex chromosomes of M. agrestis and moderate fluorescence on those of M. cabrerae and M. chrotorrhinus; however, only the heterochromatin of M. cabrerae and M. chrotorrhinus hybridized with an AT-rich satellite DNA probe (MSAT-160) isolated from M. chrotorrhinus. Hoechst 33258-bright autosomal centromeres of M. arvalis and M. cabrerae also hybridized to the probe, whereas the Hoechst 33258-bright Y chromosomes of M. arvalis and M. guentheri did not. Two pairs of autosomes in M. guentheri are comprised of six distinct regions, based upon C-banding, Hoechst 33258 staining, chromomycin A3/distamy-cin A staining, and in situ hybridization. The centromeric regions of acrocentric autosomes known to retain conserved G-banding patterns may exhibit variable hybridization intensity when different species or subspecies are compared. M. ochrogaster portrays considerable intersubspecific variability in the size and location of autosomal telomeric and interstitial C-bands that are also sites of hybridization. These latter two findings illustrate that dramatic differences in copy number of the tandem satellite array can exist at homologous chromosomal positions both within and between species.

ISSN:1424-8581    

DOI:10.1159/000133458

出版商:S. Karger AG    

年代:1993

数据来源: Karger