The CEPH consortium map of chromosome 13 is presented. This map contains 59 loci defined by genotypes generated from CEPH family DNAs with 94 different probe and restriction enzyme combinations contributed by 9 laboratories. A total of 25 loci have been placed on the map with likelihood support of at least 1000:1. The map extends from loci in the centromeric region of chromosome 13 to the terminal band of the long arm. Multipoint linkage analyses provided estimates that the male, female, and sex-averaged maps extend for 158, 203, and 178 cM respectively. The largest interval is 24 cM and is between D13Z1 (alpha RI) and ATP1AL1. The mean genetic distance between the 25 uniquely placed loci is 7 cM.

Chromosome Mapping↗

PubMed1993

Detection, cloning, and distribution of minisatellites in some mammalian genomes.

The chromosomal distribution of minisatellites (cloned and/or detected using natural or synthetic tandem repeats) is strikingly different in man and mouse. In man, the vast majority is clustered in the terminal band of a subset of chromosome arms. Interestingly, the class of shorter tandem repeats called microsatellites is widespread along the chromosomes, suggesting that minisatellites can be created or maintained only in certain regions. In order to gain a better knowledge of these areas, we have studied a sub-telomeric cosmid from the pseudoautosomal region. Sixty kilobases of human genomic DNA starting approximately 20 kilobases from the human sex chromosomes telomere have previously been independently isolated in two cosmid clones (locus DXYS14) (Cooke et al., 1985); Rouyer et al., 1986). We have studied in more detail one of the two cosmids from this locus and found that it contains four different minisatellite structures representing 20 kilobases of the cosmid. These structures are unrelated to each other or to the minisatellite family described by Jeffreys et al. (1985). They display different degrees of polymorphism correlated with varying amounts of inner homogeneity. Combined with the previous description of an additional minisatellite (Cooke et al., 1985; Inglehearn and Cooke, 1990) in the contiguous cosmid, our observation shows that these structures may represent an important proportion of the DNA in sub-telomeric regions.

Animals↗

PubMed1993

Genetic mapping through the use of synthetic tandem repeats in the mouse genome.

Polymers of arbitrary oligonucleotides can be used to detect polymorphic loci in a wide range of vertebrate genomes. Using 60 such probes, we previously reported the selection of the most efficient STR probes for polymorphism detection in the set of genomes investigated. We now report the use of this selection for the mouse genome and its contribution to genetic mapping. Twenty-three synthetic tandem repeats (STRs) sequences were probed on a recombinant inbred panel C57B1/6 x DBA/2. The loci detected are distributed in 70 linkage groups; 42 of these groups, corresponding to about 100 different polymorphic loci, include reference markers. These linkage groups appear to be evenly distributed within all the 20 mouse chromosomes with apparently no bias of repartition towards telomeres or centromeres.

Animals↗

PubMed1993

Physical mapping of the holoprosencephaly critical region on chromosome 7q36.

Holoprosencephaly (HPE) is a developmental field defect involving the brain and face. Cytogenetic deletions in patients with HPE have localized one of the HPE genes to chromosomal region 7q36. We have characterized the 7q deletions in thirteen HPE patients. The result is the construction of a high resolution physical map of 7q32-qter. As a first step towards cloning an HPE gene crucial for normal brain development, we have defined the HPE minimal critical region in 7q36 between D7S292 and D7S392.

Adult↗

PubMed1992

PCR assay for chromosome 1p deletion in small neuroblastoma samples.

Deletion of the short arm of chromosome 1 is among the most recurrent cytogenetic alterations found in neuroblastoma and has been associated with short survival. However, this prognostic information, which relies on time-consuming techniques, is not yet routinely exploited. In order to set up a reliable and simple routine test to determine 1p deletion in neuroblastoma, we have used the polymerase chain reaction to genotype neuroblastoma DNA at 2 loci containing a variable number of tandem repeats and located on the distal part of the short arm of chromosome 1. Agarose gel electrophoresis and ethidium bromide staining of the amplification products enable a simple determination of constitutional and tumor genotypes at these loci to be made. A total of 37 samples from 29 patients were studied with this technique. Loss of heterozygosity (LOH) could be identified in 8 cases. In each case the results obtained were in agreement with those achieved by the Southern procedure. This technique will be of particular interest in the pretherapeutic analysis of 1p deletions in small tumor samples obtained by fine-needle aspirates of the primary tumor. It should also enable retrospective studies from paraffin-embedded tumor fragments to be made and provide information for the analysis of tumor heterogeneity in neuroblastoma and in other tumors with 1p deletions.

Base Sequence↗

PubMed1992

Modulation of polymorphic loci detection with synthetic tandem repeat variants.

The modifications of hybridization patterns were studied when Southern blots, carrying stallions DNA samples, were probed with eight synthetic tandem repeats (STRs), related by sequence variations in the basic unit. Because STRs preferentially crosshybridize with genomic VNTRs, they usually give patterns looking more like DNA fingerprints, but we found that even small modifications in the STR monomer could cause major changes in the hybridization profiles and could induce a shift of fingerprint pattern towards the detection of only one or two loci. This enables the use of STRs as direct genetic markers for linkage analysis, without cloning of the corresponding DNA fragment. Moreover, the set of STR variants can suggest consensus sequences allowing some prediction of the banding pattern.

Animals↗

PubMed1992

Genetic mapping of three human homologues of murine t-complex genes localizes TCP10 to 6q27, 15 cM distal to TCP1 and PLG.

Human homologues of mouse t-complex genes have been cloned and localized physically to chromosome 6p or 6q. TCP1, TCP10, and PLG are human homologues of genes located in the proximal portion of the t-complex on mouse chromosome 17. We present here results of genetic mapping of these human t-complex homologues previously localized to 6q25-q27, 6q21-q27, and 6q26-q27, respectively, by physical techniques. TCP1 and PLG do not recombine with each other and are separated from TCP10 by about 15 cM, while the corresponding mouse genes are no more than 4 cM apart. Genetic mapping with markers well localized cytogenetically places TCP1 and PLG proximal to TCP10 and localizes the latter to the cytogenetic band 6q27. It is likely that the organization of human t-complex homologues on 6q is similar to that of t haplotypes rather than that of wildtype murine chromosome 17.

Animals↗

PubMed1992

Detection of polymorphic loci in complex genomes with synthetic tandem repeats.

Sixty synthetic probes mimicking minisatellite structures have been used on Southern blots bearing a set of DNA samples from a panel of complex genomes. They enable the detection of polymorphic loci in all the species tested and sometimes provide directly usable genetic markers. The general approach reported here should facilitate the study of genetic variability and the efficient development of genetic markers necessary for the mapping of complex genomes.

Animals↗

PubMed1992

CEB 13 detects a VNTR locus (Het: 93%) on chromosome 7q.

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Alleles↗