Twenty-five loci form a continuous linkage map of markers for human chromosome 7

We have constructed a primary genetic linkage map from DNA markers that define 25 loci on chromosome 7. The markers form a continuous linkage group of 141 cM in males and 340 cM in females; female genetic distances were on average more than twofold higher than those in males throughout the chromosome. The average heterozygosity of the loci was 45%. A subset of the markers can be used for efficient application of this map to studies of human genetic disease.     

Twenty-eight loci form a continuous linkage map of markers for human chromosome 1

We have used a combination of 30 serological, protein electromorphic, and DNA markers defining 28 loci to construct a linkage map of chromosome 1. These markers form a continuous linkage group of 320 cM in males and 608 cM in females; female genetic distances were on average twofold higher than those of males across the map. Among the DNA markers are 10 highly polymorphic markers reflecting loci that contain a variable number of tandem repeats, well distributed over the length of the chromosome, that will be highly efficient anchor points for application of this map to studies of human genetic disease.     

Twenty loci form a continuous linkage map of markers for human chromosome 2

We have used a combination of 20 DNA markers and 1 protein electromorph, defining 20 loci, to construct a genetic linkage map of chromosome 2. These markers form a continuous linkage group of 306 cM in males and 529 cM in females. Female map distances varied from approximately twofold higher to equivalence from those of males across the map. Among the DNA markers are six well-distributed, highly polymorphic markers reflecting loci that contain a variable number of tandem repeats that will be highly efficient anchor points for the eventual application of this map to studies of human genetic disease.     

A genetic linkage map of 32 loci on human chromosome 10

We have constructed a genetic linkage map of human chromosome 10 based on DNA probes that detect 47 restriction fragment length polymorphisms (RFLPs) at 32 different loci. Segregation data were collected on a set of multigenerational families provided by the Centre d'Etude du Polymorphisme Humain and maps were constructed using recently developed multipoint analysis techniques. The length of the sex-averaged map is 178 cM and the sex-specific map lengths are 131 cM in males and 255 cM in females. Recombination is significantly higher in female meioses. The mean distance between loci is 5.6 cM for the sex-averaged map. The genetic map spans the length of the chromosome as judged by physical localization of probes by in situ hybridization techniques and mapping of the probes on human-hamster hybrid cell lines containing all or part of chromosome 10. The informativeness of two loci near the locus responsible for multiple endocrine neoplasia type 2A (MEN-2A) has been increased by isolation of cosmids that reveal additional RFLPs at these loci.     

A comparative linkage and physical map of bovine chromosome 24 with human chromosome 18

Polymorphic microsatellites have been developed in the vicinity of nine genes on bovine chromosome (BTA) 24, all orthologous to genes on human chromosome (HSA) 18. The microsatellites have been isolated from bacterial and yeast artificial chromosome clones containing the genes. A linkage map was developed including these polymorphic markers and four anonymous, published microsatellites. Yeast artificial chromosomes containing six of these genes have also been mapped using fluorescent in situ hybridization (FISH), thereby tying the linkage map together with the physical map of BTA24. Comparing gene location on HSA18 and BTA24 identifies four regions of conserved gene order, each containing at least two genes. These genes identify six regions of conserved order between human and mouse, two more than in the human-bovine comparison. The breakpoints between regions of conserved order for human-bovine are also breakpoints in the human-mouse comparison. The centromere identifies a fifth conserved region if the BTA24 centromere is orthologous with the HSA18 centromere. Received: 17 September 1998 / Accepted: 4 December 1998     

A genetic linkage map of human chromosome 5 with 60 RFLP loci.

A genetic map of human chromosome 5 that contains 60 restriction fragment length polymorphism (RFLP) loci in one linkage group has been constructed. Segregation data using these markers and 40 large multigenerational families supplied by the Centre d'Etude du Polymorphisme Humain have been collected. Linkage analyses were performed with the program package CRI-MAP; using odds greater than 1000:1, 30 RFLP loci could be placed on the map. This genetic map spans 289 cM sex-equal, 353 cM in females, and 244 cM in males. While the relative rate of recombination for female meioses is nearly twice that of males over much of the chromosome, several instances of statistically significant excess male recombination were observed. The order of probes on the genetic map has been confirmed by their physical order as determined by somatic cell hybrid lines containing deletions of normal chromosome 5. There is concordance between the physical positions of markers and their genetic positions. Our most distal probes on the genetic map are cytologically localized to the most distal portions of the chromosome. This suggests that our genetic map spans most of chromosome 5.     

Genetic linkage map of human chromosome 21

Two of the most common disorders affecting the human nervous system, Down syndrome and Alzheimer's disease, involve genes residing on human chromosome 21. A genetic linkage map of human chromosome 21 has been constructed using 13 anonymous DNA markers and cDNAs encoding the genes for superoxide dismutase 1 (SOD1) and the precursor of Alzheimer's amyloid beta peptide (APP). Segregation of restriction fragment length polymorphisms (RFLPs) for these genes and DNA markers was traced in a large Venezuelan kindred established as a "reference" pedigree for human linkage analysis. The 15 loci form a single linkage group spanning 81 cM on the long arm of chromosome 21, with a markedly increased frequency of recombination occurring toward the telomere. Consequently, 40% of the genetic length of the long arm corresponds to less than 10% of its cytogenetic length, represented by the terminal half of 21q22.3. Females displayed greater recombination than males throughout the linkage group, with the difference being most striking for markers just below the centromere. Definition of the linkage relationships for these chromosome 21 markers will help refine the map position of the familial Alzheimer's disease gene and facilitate investigation of the role of recombination in nondisjunction associated with Down syndrome.     

A multipoint genetic linkage map of mouse chromosome 18

We have mapped 13 loci on mouse Chromosome 18 by Southern blot analysis of restriction fragment length polymorphisms among progeny from an interspecific backcross: (C57BL/6J X Mus spretus) X M. spretus. Complete haplotype analysis of 136 of these progeny was used to establish gene order and estimate genetic distances between loci. The gene order (from centromere to telomere) and recombination distances (in centimorgans) were as follows: PGK-1rs5-4.3-Tpi-10-11.8-(Egr-1, Hmg17-rs9)-2.1-Fgfa-2.2-Grl-1-10.1-(Cdx-1, Csfmr, Pdgfrb, Pdea, Rps14)-2.1-Adrb-2-22.9-Mbp. Pgk-1rs5, Tpi-10, Hmg17-rs9, and Rps14 had not been previously mapped in the mouse; Egr-1 had only been syntenically assigned to mouse Chr 18. Nine of the loci, spanning 18 cM, have homologs on the distal long arm of human Chr5--a region rich in genes encoding growth factors and receptors. An additional previously unmapped gene, Drd-1, predicted to be on mouse Chr 18 based on its human chromosomal location, was mapped to the middle region of mouse Chr 13.     

A primary genetic linkage map for human chromosome 12

A primary genetic map for human chromosome 12 has been constructed from data on 23 restriction fragment length polymorphic systems collected in 38 normal families with large sibships. Linkage analysis of the genotypic data has ordered 16 loci into a continuous genetic map of 111 cM in males and 258 cM in females. Although most of the genetic map reflects a higher rate of recombination in females relative to males, significantly more frequent recombination was observed in males than in females in intervals between loci on the distal portion of the short arm of the chromosome. The mapping data shown here will serve as a first step toward a high-resolution genetic map for human chromosome 12.     

A molecular genetic linkage map of mouse chromosome 18 reveals extensive linkage conservation with human chromosomes 5 and 18

An interspecific backcross between C57BL/6J and Mus spretus was used to generate a molecular genetic linkage map of mouse chromosome 18 that includes 23 molecular markers and spans approximately 86% of the estimated length of the chromosome. The Apc, Camk2a, D18Fcr1, D18Fcr2, D18Leh1, D18Leh2, Dcc, Emb-rs3, Fgfa, Fim-2/Csfmr, Gnal, Grl-1, Grp, Hk-1rs1, Ii, Kns, Lmnb, Mbp, Mcc, Mtv-38, Palb, Pdgfrb, and Tpl-2 genes were mapped relative to each other in one interspecific backcross. A second interspecific backcross and a centromere-specific DNA satellite probe were used to determine the distance of the most proximal chromosome 18 marker to the centromere. The interspecific map extends the known regions of linkage homology between mouse chromosome 18 and human chromosomes 5 and 18 and identifies a new homology segment with human chromosome 10p. It also provides molecular access to many regions of mouse chromosome 18 for the first time.     

Genetic map of nine polymorphic loci comprising a single linkage group on rat chromosome 10: evidence for linkage conservation with human chromosome 17 and mouse chromosome 11.

Seven genes and two anonymous markers were mapped to a single linkage group on rat chromosome 10 using progeny of an F2 intercross of Fischer (F344/N) and Lewis (LEW/N) inbred rats. Two genes, the neu oncogene or cellular homologue of the viral oncogene erbb2 (ERBB2) and growth hormone (GH) were mapped by Southern blot analysis of restriction fragment length polymorphisms. Five genes, embryonic skeletal myosin heavy chain (MYH3), androgen binding protein/sex hormone binding globulin (SHBG), asialoglycoprotein receptor (hepatic lectin)-1 (ASGR1), ATP citrate lysase (CLATP), and pancreatic polypeptide (PPY), and two anonymous markers, F16F2 and F10F1, were mapped using PCR amplification techniques. The PCR-typable polymorphic markers for the five genes were also highly polymorphic in 10 other inbred rat strains (SHR/N, WKY/N, MNR/N, MR/N, LOU/MN, BN/SsN, BUF/N, WBB1/N, WBB2/N, and ACI/N). These markers should be useful in genetic analysis of traits described in inbred rat strains, as well as in genetic monitoring of such strains. The loci in this linkage group covered 50 cM of rat chromosome 10 with the following order: MYH3, SHBG/ASGR1 (no recombinants detected), F16F2, ERBB2, CLATP, PPY, GH, and F10F1. Comparative gene mapping analysis indicated that this region of rat chromosome 10 exhibits linkage conservation with regions of human chromosome 17 and mouse chromosome 11.     

An updated linkage and comparative map of porcine chromosome 18

Swine chromosome 18 (SSC18) has the poorest marker density in the USDA-MARC porcine linkage map. In order to increase the marker density, seven genes from human chromosome 7 (HSA7) expected to map to SSC18 were selected for marker development. The genes selected were: growth hormone releasing hormone receptor (GHRHR), GLI-Kruppel family member (GLI3), leptin (LEP), capping protein muscle Z-line alpha 2 subunit (CAPZA2), beta A inhibin (INHBA), T-cell receptor beta (TCRB) and T-cell receptor gamma (TCRG). Large-insert clones (YACs, BACs and cosmids) that contained these genes, as well as two previously mapped microsatellite markers (SW1808 and SW1984), were identified and screened for microsatellites. New microsatellite markers were developed from these clones and mapped. Selected clones were also physically assigned by fluorescence in situ hybridization (FISH). Fifteen new microsatellite markers were added to the SSC18 linkage map resulting in a map of 28 markers. Six genes have been included into the genetic map improving the resolution of the SSC18 and HSA7 comparative map. Assignment of TCRG to SSC9 has identified a break in conserved synteny between SSC18 and HSA7.     

A genetic linkage map of markers for human chromosome 20

A continuous genetic linkage map with five polymorphic DNA markers, including one that defines a locus containing a variable number of tandem repeats (VNTR), has been constructed from genotypic analysis of 59 large reference families. The map spans a genetic distance of 105 cM in males and 115 cM in females and provides initial anchor points for a high-resolution map of human chromosome 20.     

A 2-cM genetic linkage map of human chromosome 7p that includes 47 loci.

A new high-resolution genetic linkage map for human chromosome 7p has been constructed. The map is composed of 47 loci (54 polymorphic systems), 19 of which are uniquely placed with odds of at least 1000:1. Four genes are represented, including glucokinase (GCK, ATP:D-hexose-6-phosphotransferase, EC 2.7.1.2) which was mapped via a (CA)n dinucleotide repeat polymorphism. The sex-average map measures 94.4 cM and the male and female maps measure 73.2 and 116.1 cM, respectively. We believe that the genetic map extends nearly the full length of the short arm of chromosome 7 since a centromere marker has been incorporated, and the most distal marker, D7S21, has been cytogenetically localized by in situ hybridization to 7p22-pter. The average marker spacing is 2 cM, and the largest interval between uniquely placed markers is 13 cM (sex-average map). Overall, female recombination was observed to be about 1.5 times that of males, and a statistically significant sex-specific recombination frequency was found for a single interval. The map is based on genotypic data gathered from 40 CEPH reference pedigrees and was constructed using the CRI-MAP program package. The map presented here represents a combined and substantially expanded dataset compared to previously published chromosome 7 maps, and it will serve as a "baseline" genetic map that should prove useful for future efforts to develop a 1-cM map and for construction of a contiguous clone-based physical map for this chromosome.     

A genetic linkage map of 96 loci on the short arm of human chromosome 3.

We constructed a genetic map of 96 loci on the short arm of human chromosome 3 (3p) in 59 families provided by the Centre d'Etude du Polymorphisme Humaine (CEPH). Twenty-nine continuously linked loci were placed on the map with likelihood support of at least 1000:1; one locus, D3S213, was placed on the map with likelihood support of 871:1; D3Z1, an alpha satellite centromeric repeat probe, was placed on the map with likelihood support of 159:1; 65 loci were assigned regional locations. The average heterozygosity of the uniquely ordered markers was 49%. The map extends from 3p26, the terminal band of 3p, to the centromere (from D3S211 to D3Z1). Multipoint linkage analysis indicated that the male, female, and sex-averaged maps extend for 102, 147, and 116 cM, respectively. The mean genetic distance between uniquely ordered loci on the sex-averaged map was 4.0 cM. Probe density was greatest for the region of 3p between D3F15S2e and the telomere. The sex-averaged map contained two intervals greater than 10 cM. Seventeen probes were localized by fluorescence in situ hybridization. The loci described in this report will be useful in building an integrated genetic and physical map of this chromosome.     

An extended genetic linkage map of markers for human chromosome 10

We have extended, in both directions, our recently published genetic map of markers for human chromosome 10 by the addition of 10 newly defined arbitrary loci. The map now covers 230 cM in males and 329 cM in females. In addition, three new markers, one of them a new RFLP at the IRBP gene locus, have been mapped in the vicinity of the locus responsible for multiple endocrine neoplasia type 2A (MEN2A). A significantly higher frequency of recombination in males than in females was observed near both ends of the new map.     

The CEPH consortium linkage map of human chromosome 2

This paper describes the Centre d'Etude du Polymorphisme Humain (CEPH) consortium linkage map of chromosome 2. The map contains 36 loci defined by genotyping generated from the CEPH family DNAs. A total of 73 different markers were typed by 14 contributing laboratories; of these, 36 loci are ordered on the map with likelihood support of at least 1000:1. Markers are placed along the length of the chromosome but no markers were available to anchor the map at either telomere or the centromere. Multilocus linkage analysis has produced male, female, and sex-averaged maps extending for 261, 430, and 328 cM, respectively. The sex-averaged map contains five intervals greater than 15 cM and the mean genetic distance between the 36 uniquely placed loci is 9.1 cM.     

The CEPH consortium linkage map of human chromosome 1

This paper describes the Centre d'Etude du Polymorphisme Humain (CEPH) consortium linkage map of human chromosome 1. The map contains 101 loci defined by genotypes generated from CEPH family DNAs with 146 different contributions from 11 laboratories. A total of 58 loci are uniquely placed on the map with likelihood support of at least 1000:1. The map extends from loci in the terminal bands of both chromosome arms (locus D1Z2 in 1p36.3 and D1S68 in 1q44) and is anchored at the centromere by the D1Z5 alpha-satellite polymorphism. With the exception of a single locus, the remaining loci are arrayed on the fixed map in short intervals and their possible locations are indicated. Multipoint linkage analyses provided estimates that the male, female, and sex-averaged maps extend for 308, 478, and 390 cM, respectively. The sex-averaged map contains only four intervals greater than 15 cM, and the mean genetic distance between the 58 uniquely placed loci is 6.7 cM.     

A genetic linkage map of human chromosome 9q.

A genetic linkage map of human chromosome 9q, spanning a sex-equal distance of 125 cM, has been developed by genotyping 26 loci in the Venezuelan Reference Pedigree. The loci include 12 anonymous microsatellite markers reported by Kwiatkowski et al. (1992), several classical systems previously assigned to chromosome 9q, and polymorphisms for the genes tenacin (HXB), gelsolin (GSN), adenylate kinase 1 (AK1), arginosuccinate synthetase (ASS), ABL oncogene (ABL1), ABO blood group (ABO), and dopamine beta-hydroxylase (DBH). Only a marginally significant sex difference is found along the entire length of the map and results from one interval, between D9S58 and D9S59, that displays an excess of female recombination. A comparison of the genetic map to the existing physical data suggests that there is increased recombination in the 9q34 region with a recombination event occurring every 125-400 kb. This map should be useful in further characterizing the relationship between physical distance and genetic distance, as well as for genetic linkage studies of diseases that map to chromosome 9q, including multiple self-healing squamous epithelioma (MSSE), Gorlin syndrome (NBCCS), xeroderma pigmentosum (XPA), nail-patella syndrome (NPS1), torsion dystonia (DYT1), and tuberous sclerosis (TSC1).     

The CEPH consortium primary linkage map of human chromosome 10

The first CEPH consortium map, that of chromosome 10, is presented. This primary linkage map contains 28 continuously linked loci defined by genotypes generated from CEPH family DNAs with 37 probe and enzyme combinations. Cytogenetic localization of some of the genetic markers indicates that the consortium map extends, at least, from 10p13 to 10q26. The order of loci on the consortium map agrees with the physical localization data. The female map spans 309 cM (206 cM if an approximation of interference is included in the mapping function used to construct the map), and the mean genetic distance of intervals is 11 cM (7 cM). Also presented are maps of chromosome 10 from each of five CEPH collaborating laboratories, based on genotypes for all relevant markers in the CEPH database. The CEPH consortium map of chromosome 10 should be useful for localization of any gene of interest falling within the span covered. The genotypes in the chromosome 10 consortium map database are now available to the scientific community.