Proc. Nati. Acad. Sci. USA Vol. 89, pp. 104-108, January 1992 Medical Sciences Construction of a map of 16 by using radiation hybrids (somatic hybrids/physical maps/multiple pairwise analysis) I. CECCHERINI*t, G. ROMEO*, S. LAWRENCEt, M. H. BREUNING§, P. C. HARRIS¶, H. HIMMELBAUERII, A. M. FRISCHAUFII, G. R. SUTHERLAND**, G. G. GERMINOtt, S. T. REEDERS#t, AND N. E. MORTONt *Laboratorio di Genetica Molecolare, Istituto G. Gaslini, 16148 Genova, Italy; tDepartment of Community Medicine, University of Southampton, Southampton General Hospital, Southampton S09 4XY, United Kingdom; §Department of Genetics, State University of Leiden, Wassenaarseweg 72-2333 AL Leiden, The Netherlands; 1Medical Research Council Molecular Haematology Unit, Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom; IIImperial Cancer Research Fund, P.O. Box 123, Lincoln's Inn Fields, London WC2A 3PX, United Kingdom; **Department of and Molecular Genetics, Adelaide Children's Hospital, North Adelaide 5006, Australia; ttDepartment of Nephrology, School of Medicine, P.O. Box 3333, Yale University, New Haven, CT 06510; and tHoward Hughes Medical Institute, Yale University, New Haven, CT 06520 Contributed by N. E. Morton, September 9, 1991

ABSTRACT A human-hamster cell hybrid carrying a found to be mostly consistent with currently available phys- single copy of as the only human genetic ical and genetic linkage data. material was irradiated with a single dose of -rays (7000 rads; 1 rad = 0.01 Gy) and then fused with a - MATERIALS AND METHODS deficient hamster cell line (RJKM) to generate radiation hy- RJ83.1FT is a hamster-human hybrid cell line containing a brids retaining unselected fragments of this human chromo- single chromosome 16 (as the only human genetic material), some. In two experiments, 223 hybrids were isolated in hypo- which is retained in about 95% of cells in absence of delib- xanthine/aminopterine/thymidine (HAT) medium and erate selection. This hybrid originated from the fusion of an screened with 38 DNA probes, corresponding to anonymous HPRT-deficient hamster cell line (RJK88) with human lym- DNA or sequences localized on chromosome 16. The most phocytes. RJKM, a Chinese hamster cell line deficient in likely order and location of the 38 DNA sequences were thymidine kinase activity, was obtained from T. Mohandas established by multiple pairwise analysis and scaled to estimate (Harbor General Hospital, University of California, Los physical distance in megabases. The order and the distances Angeles). Cells were grown at 370C in RPMI 1640 medium thus obtained are mostly consistent with available data on supplemented with 18% (vol/vol) fetal calf serum, penicillin genetic and physical mapping ofthese markers, illustrating the (100 units/ml), and streptomycin (100 ttg/ml). usefulness of radiation hybrids for mapping. Prior to irradiation, RJKM cells were grown in the pres- ence of 50 nM 5-bromodeoxyuridine (BrdUrd) for 4 days and Somatic cell hybrids represent a powerful approach for in its absence for 2 days prior to the experiment to minimize mapping of human DNA sequences and a useful reagent for both thymidine kinase-sufficient revertants and the intracel- cloning. In recent years various procedures have been de- lular content of BrdUrd. On the day of fusion, 1 x 107 veloped for the transfer of small fragments of the human RJ83.1FT cells were treated with trypsin, washed, and re- into a rodent-cell background. One ofthese methods suspended in 10 ml of serum-free RPMI 1640 medium. This is represented by the irradiation and fusion gene transfer cell suspension was y-irradiated at 0C using a Gammacell technique, first described by Goss and Harris (1). Irradiation- 1000 apparatus (Atomic Energy, Ottawa) at a rate of 437 reduced cell hybrids have been generated for selected or rads/min (1 rad = 0.01 Gy) for about 16 min (exposure, 7000 unselected portions of the to introduce DNA rads). An equal proportion of irradiated RJ83.1FT cells and fragments carrying responsible for inherited human unirradiated RJKM cells were mixed and centrifuged, and 0.5 diseases into a rodent background (2-4). These hybrids have ml of50% (wt/vol) polyethylene glycol Mr 1000 in RPMI 1640 also proved to be useful for mapping purposes (5-9). In medium supplemented with 10% (vol/vol) dimethyl sulfox- particular, maps of the proximal and distal long arm of ide, was added to the cell pellet, following a protocol essen- the tially identical to a published procedure (13). After fusion, have been constructed by analyzing cells were plated in 100-mm plastic dishes and incubated at cosegregation of chromosome 21-specific DNA sequences in 370C for 2-3 weeks. Hypoxanthine/aminopterin/thymidine human-hamster radiation hybrids that were not subjected to (HAT) medium was added 2 days after fusion and replaced deliberate selection for any particular chromosome 21 gene every 3-4 days thereafter. HAT-resistant colonies, visible at (10, 11). By using such radiation hybrids, it has been possible 10-14 days, were isolated with cloning cylinders. Only one to order human DNA sequences independently of any other colony per dish was picked and expanded for analysis. No information and to estimate distances between loci on the colonies were observed in control dishes of irradiated basis of the principle that the probability ofcotransference of RJ83.1FT cells plated in HAT medium. Revertant RJKM a pair of loci decreases with the distance between them. We colonies were observed at a frequency of 5 x 10-6. have followed this approach to construct a radiation map of The cloned DNA sequences used as probes in this study are chromosome 16 starting from a human-hamster hybrid re- listed in Table 1. Probe 16.2.4 was isolated by B. Wirth at the taining human chromosome 16 as its only human genetic Imperial Cancer Research Fund. DNA (10 ,ug) prepared from component. Retention frequencies for each of38 markers and the hybrids and the parental cell lines was digested with Taq cotransference frequencies for each pair of markers were I, HindIII, Msp I, or Pst I, electrophoresed in 0.8% agarose, submitted to multiple pairwise analysis. The best order of transferred to a nylon membrane (Hybond, Amersham), and markers was sought and distances were scaled to the esti- hybridized to each probe by following established conditions mated physical lengths ofthe p and q arms (12). This map was (31). Each filter was reused up to 10 times.

The publication costs of this article were defrayed in part by page charge Abbreviations: Mb, megabase(s); lod, logarithm of odds; cR, centi- payment. This article must therefore be hereby marked "advertisement" ray(s). in accordance with 18 U.S.C. §1734 solely to indicate this fact. tTo whom reprint requests should be addressed. 104 Downloaded by guest on October 1, 2021 Medical Sciences: Ceccherini et al. Proc. Natl. Acad. Sci. USA 89 (1992) 105

Table 1. Radiation hybrid map of chromosome 16 Informative Retention Isolated Ref. Flanking hybrids, frequency reactions for Probe marker Support no. 1 2 + - locus (5'HVR) 5'HVR D16S85 1.5 0.30 0.26 14 D16S85 3'HVR D16S21 2.7 0.30 0.23 14 D16S21 FR3.42 D16S84 -0.2 30 0.27 15 D16S84 CMM65 D16S139 1.1 94 0.27 0.25 0.02 16 D16S139 N54 D16S125 0.0 94 0.27 0.20 17 D16S125 26.6 D16S94 0.0 29 0.24 18 D16S94 VK5 D16S138 1.5 96 0.27 0.24 19 D16S138 N2 D16S63 0.0 30 0.23 20 D16S63 CRI0327 D16S80 4.1 30 0.23 14 D16S80 24.1 D16S144 0.0 30 0.27 21 D16S144 LOM2B D16S45 0.0 30 0.27 22 D16S45 CRI090 D16S82 0.0 30 0.27 14 D16S82 41.1 D16S81 0.0 30 0.27 18 D16S81 3.15 D16S143 0.0 96 0.27 0.18 0.01 0.01 18 D16S143 16/116 D16S119 10.8 30 0.24 23 D16S119 2.36 D16S3 1.3 30 0.20 24 D16S3 ACH92 D16S79 1.3 30 0.23 25 D16S79 36.1 D16S% 3.6 30 0.27 18 D16S96 VK20B D16S120 18.9 30 0.33 0.24 0.02 0.02 26 D16S120 1.57 D16S101 3.4 30 0.37 24 D16S101 VK22 D16S36 5.4 96 0.33 0.47 0.09 0.04 26 D16S36 16/12 cen 9.3 30 0.67 0.10 0.03 23 cen D16Z3 0.1 D16Z3 HUR195 (16.2.4) 2.5 30 0.83 0.64 0.23 0.04 27 (16.2.4) 16.2.4 D16S123 14.7 30 0.70 0.07 0.07 D16S123 2.46 D16S124 13.4 30 0.40 0.03 0.16 24 D16S124 1.99 D16S107 8.2 95 0.43 0.20 0.05 0.03 24 D16S107 VK26.F13 D16S179 0.7 30 0.32 0.03 26 D16S179 16/67 D16S10 0.1 30 0.30 23 D16S10 ACHF3.A3 D16S177 0.0 30 0.29 28 D16S177 16/63 Uvo 0.9 30 0.27 23 Uvo V%1 D16S4 0.6 90 0.23 0.08 0.01 0.02 29 D16S4 ACH207 TAT 12.1 30 0.27 0.03 25 TAT BSO.9 D16S14 0.2 0.27 0.24 0.02 30 D16S14 ACH202 D16S162 0.3 30 0.23 25 D16S162 16/08 D16S15 5.1 30 0.27 23 D16S15 ACH208 D16S176 2.3 30 0.20 25 D16S176 16/60 D16S5 4.3 30 0.23 23 D16S5 ACH224 96 0.17 0.12 25 1, First experiment; 2, second experiment; +, positive isolated reactions; -, negative isolated reactions. Local support is log1o(L1, L2), where L1 is the likelihood under the favored order and L2 is the likelihood under transposition with the flanking locus (32). For each hybrid a record was created with a field for each to construct the map. The order shown in Table 1 maximized of the probes, coded 0, 1, or 8 for negative, positive, or not the likelihood on the assumption of independent lod scores done, respectively. There were two experiments. In the first (except for the order of D16S84 and D16S21, which is based 37 probes were used on 58 hybrids. In the second 14 probes on previous long-range restriction mapping) (15). The radia- were used on 165 hybrids. No hybrid was positive for all tion hybrids give trivial support for the alternative order of tested probes. However, 28 hybrids in the first experiment markers (Z = 0.2, odds = 1.7:1). A lod testing the preferred and 99 hybrids in the second experiment were negative with order against an inversion of a pair of probes is called local all probes used and so were uninformative with respect to support. Local support is weak also for the four clusters differential retention and cotransference. These hybrids were (D16S139, D16S125, D16S94), (D16S138, D16S63), (D16S80, excluded, leaving a maximum of 30 observations on each D16S144, D16S45, D16S82, D16S81, D16S143), and probe in the first experiment and 66 in the second (Table 1). (D16S10, D16S177) of the short arm, and for the two clusters Retention and cotransference frequencies were converted to (D16S107, D16S179, D16S10, D16S177, UVO) and (TAT, estimates of association (6) and corresponding logarithm of D16S14) ofthe long arm. For other markers, local support >2 odds (lod scores) (Z) and submitted to multiple pairwise (corresponding to odds of 100:1) is strong support for order. analysis by the MAP program (32, 33) as described by Many loci, especially near the , give isolated Lawrence et al. (12). In a given analysis only paracentric loci reactions discordant with flanking markers. D16Z3 and (in the same chromosome arm) were mapped, to satisfy the D16S123 show a remarkably high frequency ofpositive (0.23) assumption that maximal retention is terminal. and negative (0.16) isolated reactions, respectively. The order and support shown in Table 1 were based on RESULTS separate estimates of the asymptote L for each experiment Experiments 1 and 2 were analyzed separately and found to and chromosome arm (Table 2). L denotes the conditional give consistent locus orders. Therefore, the data were pooled probability that a locus separated from its centromere be Downloaded by guest on October 1, 2021 106 Medical Sciences: Ceccherini et al. Proc. Natl. Acad. Sci. USA 89 (1992) Table 2. x2tests (E = 0,p = 1, K = 1) relative order of the probes within the clusters (D16S107, X2 value D16S179, D16S10, D16S177, UVO) and (TAT, D16S14) on 16q is also weakly supported by our data. A higher radiation p arm q arm dose or a larger sample should provide order within these Hypothesis 1 2 1 2 Total clusters. The decrease of the retention frequencies of the probes L= P 331.00 133.48 221.88 61.22 747.58 tested (Table 1), observed in both arms of the chromosome L = Pmin 216.42 125.82 116.28 37.07 495.59 from the centromere to the , suggests a preferential L 211.18 87.69 115.58 21.91 436.36 retention in our radiation hybrids of some DNA sequences Value of L 0.178 0.170 0.160 0.160 near the centromere or else selection against subtelomeric 1, First experiment; 2, second experiment. sequences. This observation is in keeping with a previous report (6) and with a theoretic model that predicts the prefer- retained, whereas Pi is the marginal probability that locus i is ential retention of both centromere and in radiation retained. The hypothesis of equal retention frequencies (L = hybrids (12). However, the slight increase of the presence of P) is strongly rejected (x2 = 311.22) as is the hypothesis that human fragments containing the p-telomeric locus D16S85 is L is the minimum value of Pi (X2 = 59.23). As described by too weak to confirm the expected preferential retention of the Lawrence et al. (12), these tests were based on the assump- telomere ofthe short arm, while we could not test the retention tions of no interference (p = 1) and consistent maps for ofthe q-telomere because our most distal probe D16S5 is 18% conditional retention and loss (K = 1). of the long arm away from its telomere. In the pooled data, residual x2 is acceptable for the p arm A possible radiosensitivity ofthe centromeric region might but surprisingly small for the q arm (Table 3). This probably account for the positive and negative isolated reactions that reflects cotransference frequencies less than L, which give a have been observed clustered around the centromere and lod score of zero and an expected lod score near zero, decreased toward the telomeres (Table 1). Since isolated reducing the degrees of freedom from its conventional value positive and negative reactions cannot be explained only in of n - k, where n is the number of observed lod scores and term of the postulated preferential retention of the cen- k is the number ofparameters estimated. For constructing the tromere, a different mechanism (perhaps a single ionization) map and testing hypotheses this hypovariability is inconse- must be invoked that is able to cut out short DNA fragments: quential. It is absent from the p arm since several loci with once generated they might then be preferentially retained at zero distance were pooled into megaloci, whereas small but some locations (e.g., high frequency of positive reactions at nonzero intervals in the q arm were not pooled. We did not locus D16Z3) or lost at other locations (high frequency of attempt error filtration because the etiology of isolated re- negative reactions at locus D16S123). Radiosensitivity actions is complex and not attributable solely to error (12). and/or preferential retention of the centromeric heterochro- Estimates of map length in centirays (cR) are dosage- matin, which is proximal in the long arm, might also play a dependent and were, therefore, scaled to megabases (Mb) role in the apparent increase of the length of 16q when it is under the plausible but unproven assumption that radiation estimated in radiation units (cR), as observed above. breakage is uniform on the physical map. The distance The multiple pairwise analysis enabled us to estimate dis- between 5'-HVR and the centromere was estimated by MAP tances between pairs of adjacent loci in addition to their most to be 152 cR, which we take as the length of the p arm likely order. The reliability ofthe map thus obtained has been corresponding to 39 Mb (34). The distance between the assessed by comparing the location of the 38 probes consid- centromere and D16S5 was estimated as 235 cR. The distal ered, as suggested by the present work, with that known by marker is proximal to band q24.2, leaving unspanned the previous genetic, physical, and cytogenetic assignment, as subtelomeric 18% ofthe q arm (35). From a physical estimate shown in Table 4. The most likely order ofthe 38 human DNA of 59 Mb for 16q (34), we calculate that the map spans 48 Mb sequences is, with few exceptions, in agreement with the order of the q arm. The cR estimates are in reasonable agreement, of markers deduced from linkage data (16, 37, 38), from although they suggest a larger map for the q arm than one somatic cell hybrids carrying rearranged portions of this might expect from the physical length. Information about this chromosome (36, 39), and from physical pulsed-field gel map is given in Table 4. electrophoresis data (15, 39, 40). One of the exceptions is the order pter-D16S21-D16S84-cen, which is based on long- range restriction mapping (15) but is weakly contradicted by DISCUSSION our radiation hybrid data (Z = 0.2 and odds = 1.7:1 for the The analysis of the data obtained with radiation hybrids of alternative order). Other apparent inconsistencies found in the chromosome 16 suggests some conclusions concerning the order of some loci, as predicted by our radiation map of the use of this mapping approach that are of general interest. long arm with respect to the map recently obtained using a Clusters of probes whose relative order is weakly sup- panel of somatic cell hybrids carrying rearranged portions of ported by our radiation hybrid data have been identified in 16q (36), may be due to their weak local support, as discussed different regions of the chromosome 16 (Table 1). In partic- above. ular no resolution was achieved for the distal part of 16p The discrepant location of both D16S124 and D16S36, where the numerous sequences, which have been ordered by which our radiation data mapped with strong support more other means, are very close to each other (15, 16, 19); since proximal, respectively, in the long and in the short arms with not all of these sequences have been separated by radiation respect to the rearranged somatic cell hybrids map, may be events, we could only order clusters within which the relative due to partial hybridization on another location as suggested order of the individual sequences cannot be determined. The from loci duplications reported for chromosome 16 (41). The physical distances between some probes, obtained Table 3. Arm lengths with megaloci through radiation hybrid data, are in agreement with pulsed- Arm Mb cR cR scaled Ratio x2 df field gel electrophoresis data available for the same intervals of the short arm. In particular, as shown in Table 4, the p 39 152 39 0.26 257.19 256 physical distance between D16S84 and D16S94 has been q 59* 235 48 0.20 154.83 238 estimated to be <1 Mb (39), which fits with our estimate of df, Degrees of freedom. 1 Mb. Similarly D16S45 is -2 Mb away from D16S63 and *Including region distal to D16S5. within 200 kilobases of D16S144 (39). On the other hand the Downloaded by guest on October 1, 2021 Medical Sciences: Ceccherini et al. Proc. Natl. Acad. Sci. USA 89 (1992) 107

Table 4. Location database for chromosome 16 Radiation Cytogenetic Genetic map, cM Physical hybrid map, Locus Region assignment Male Both sexes Female map, Mb Mb pter pter 0.0 0.0 (5'HVR) A p13.3 0.0 D16S85 A p13.3 0.0 0.0 0.0 0.35 0.8 D16S21 B p13.3 3.0 0.5 1.10 1.7 D16S84 D p 7.0 1.0 2.00 1.7 D16S139 E p13 2.2 D16S125 E p13 2.2 D16S94 E p13.3 14.6 <3.00 2.7 D16S138 p13 3.5 D16S63 F p13 14.0 2.0 3.5 D16S80 F pl3.3-pl3.13 4.8 D16S144 F pter-pl3.1 4.8 D16S45 F pter-p13 17.5-19.9* 2.5-3.2* 4.8 D16S81 F p13.3 4.8 D16S82 F p13.3 4.8 D16S143 F pter-pl3.1 4.8 D16S119 F pl3.3-pl3.13 7.9 D16S3 F pl3.3-pl3.13 9.1 D16S79 G pl3.13-pl3.11 38.2 10.5 D16S96 G pl3.13-pl3.11 13.2 D16S120 K pl3.11-pll.2 20.0 D16S101 K pl3.11-pll.2 24.3 D16S36 G pter-p13 32.0 cen cen 39.0 D16Z3 M qll.2 43.1 (16.2.4) 46.6 D16S123 NO ql2-q13 54.4 D16S124 T ql3-q21 61.7 D16S107 Q ql3-q21 65.8 D16S179 p q 66.6 D16S10 Q ql3-q22.1 57.2 67.1 D16S177 Q q 67.3 Uvo T q22.1 68.1 D16S4 S q22.1 60.0 68.8 TAT x q22.1 60.0 72.1 D16S14 w q22.1 72.9 D16S162 w ql2-qter 73.8 D16S15 VWXY q22-q24 77.3 D16S176 x q 81.2 D16S5 x q23.1-q24 87.0 qter qter 98.0 Regions (A-Z) have been defined through the breakpoints present in somatic cell hybrids carrying rearranged portions of the short (25) and the long (36) arm of chromosome 16, as follows: pter(A)JS(B)PK32(C)CY14(D)NOH1(E)- 23HA(F)CY19(G)SMI/FRA16A(H)PK30/PAR(I)CY13(J)CY15(K)CY12(L)centromere(M)CY8(N)CY135(0)CY7(P)- CY13OP(Q)CY125P/FRA16B(R)CY13OD(S)CY4(T)CY6/CY125D(U)CY5(V)CY170(W)CY124(X)CY120(Y)CY2/ CY3(Z)qter. Cytogenetic assignment and genetic and physical estimates of distance have been reported (15, 16, 19, 36-39). The physical map distance was from pulsed-field gel electrophoresis data. Estimates of distance of the radiation hybrids map in centirays were scaled to megabases according to the total length of chromosome 16, as shown in Table 3. *The two values represent different estimates of the same interval, as reported in the literature.

apparent overestimate of the distances between the most We thank S. Castagnola, S. Giambarrasi, A. De Lapi, G. Caridi, distal probes in 16p and the p-telomere might be due to the and G. Panzica for their technical assistance; Drs. R. K. Moyzis, G. mentioned preferential retention of the telomeric sequences, Scherer, R. Kemler, B. Wirth, and V. J. Hyland for providing probes which accounts then for the apparent increase in the length for the characterization ofRH; Dr. M. Rocchi for providing the initial of this region. monochromosomal hybrid; and Prof. I. Barrai and Dr. V. J. Hyland for helpful discussion. This work was supported by "Progetto In spite of some inconsistencies, which still need to be Finalizzato Ingegneria Genetica", Consiglio Nazionale delle reconciled, possibly by a different mapping approach, radi- Ricerche (Rome). ation hybrids have been confirmed to be a powerful tool to obtain order and distance between pair of markers. The 1. Goss, S. J. & Harris, H. (1975) Nature (London) 255, 1445- 1458. integration of the map obtained through radiation hybrids 2. Cox, D. R., Pritchard, C. A., Uglum, E., Casher, D., Kobori, with available cytogenetic, genetic, and physical data may J. & Myers, R. M. (1989) Genomics 4, 397-407. then represent an useful method to construct location data- 3. Glaser, T., Rose, E., Morse, H., Housman, D. & Jones, C. bases for human , as shown in Table 4 for (1990) Genomics 6, 48-64. chromosome 16 and reported for other human chromosomes 4. Goodfellow, P. J., Povey, S., Nevanlinna, H. A. & Goodfel- (12, 32). low, P. N. (1990) Somatic Cell Mol. Genet. 16, 163-171. Downloaded by guest on October 1, 2021 108 Medical Sciences: Ceccherini et al. Proc. Natl. Acad Sci. USA 89 (1992) 5. Graw, S., Davidson, J., Gusella, J., Watkins, P., Tanzi, R., 22. Harris, P. C., Reeders, S. T., Lehmann, 0. J. & Tanzi, R. E. Neve, R. & Patterson, D. (1988) Somatic Cell Mol. Genet. 14, (1989) Cytogenet. Cell Genet. 51, 1011 (abstr.). 233-242. 23. Harris, P. C., Lalande, M., Stroh, H., Bruns, G., Flint, A. & 6. Benham, F., Hart, K., Crolla, J., Bobrow, M., Francavilla, M. Latt, S. A. (1987) Hum. Genet. 77, 95-103. & Goodfellow, P. N. (1989) Genomics 4, 509-517. 24. Breuning, M. H., Saris, J. J., Wapenaar, M. C., den Dunnen, 7. Mellot, J. K., Bhowmick, N., van Tuinen, P., Hornstra, I. K. J. T., van Ommen, G. J. B. & Pearson, P. L. (1988) in Ap- & Yang, T. P. (1990) Genome Mapping and Sequencing (Cold proaches to the Pathogenesis ofPolycystic Kidney Disease, ed. Spring Harbor Lab., Cold Spring Harbor, NY), p. 120 (abstr.). Carone, F. A. (TPNT, Chicago), pp. 17-21. 8. Naylor, S. L., Xiang, R.-H., Theune, S., Mudd, M., Fung, J., 25. Hyland, V. J., Grist, S., Callen, D. F. & Sutherland, G. R. Riehl, E., Ghosh-Choudhury, N. & Killary, A. (1990) Genome (1988) Am. J. Hum. Genet. 42, 373-379. Mapping and Sequencing (Cold Spring Harbor Lab., Cold 26. Hyland, V. J., Fernandez, K. E. W., Callen, D. F., MacKin- Spring Harbor, NY), p. 126 (abstr.). non, R. N., Baker, E. G., Friend, K. & Sutherland, G. R. 9. Wolfe, J., Florian, F., Fitzgibbon, J., Hornigold, N., Flomen, (1989) Hum. Genet. 83, 61-66. R. & Goodfellow, P. N. (1990) Genome Mapping and Sequenc- 27. Moyzis, R. K., Albright, K. L., Bartholdi, M. F., Cram, L. S., ing (Cold Spring Harbor Lab., Cold Spring Harbor, NY), p. 195 Deaven, L. L., Hildebrand, C. E., Joste, N. E., Longmire, (abstr.). J. L., Meyne, J. & Schwarzacher, R. T. (1987) Chromosoma 10. Cox, D. R., Burmeister, M., Price, E. R., Kim, S. & Myers, 95, 375-386. R. M. (1990) Science 250, 245-250. V. Fratini, A., Bates, L. J,, Gedeon, 11. Burmeister, M., Kim, S. W., Roydon Price, E., de Lange, T., 28. Mulley, J. C., Hyland, J., Tantravahi, U., Myers, R. M. & Cox, D. R. (1991) Genomics A. K. & Sutherland, G. R. (1989) Hum. Genet. 82, 131-133. 9, 19-30. 29. Natt, E., Magenis, R. E., Zimmer, J., Mansouri, A. & Scherer, 12. Lawrence, S., Morton, N. E. & Cox, D. R. (1991) Proc. Nati. G. (1989) Cytogenet. Cell Genet. 50, 145-148. Acad. Sci. USA 88, 7477-7480. 30. Westphal, E.-M., Natt, E., Grimm, T., Odievre, M. & Scherer, 13. Brahe, C. & Serra, A. (1981) Somatic Cell Genet. 7, 109-115. G. (1988) Hum. Genet. 79, 260-264. 14. Reeders, S. T., Keith, T., Green, P., Germino, G. G., Barton, 31. Roncuzzi, L., Fadda, S., Mochi, M., Prosperi, L., Sangiorgi, N. J., Lehmann, 0. J., Brown, V. A., Phipps, P., Morgan, J., S., Santamaria, R., Sbarra, D., Besana, D., Morandi, D., Bear, J. C. & Parfrey, P. (1988) Genomics 3, 150-155. Rocchi, M. & Romeo, G. (1985) Am. J. Hum. Genet. 37, 15. Harris, P. C., Barton, N. J., Higgs, D. R., Reeders, S. T. & 407-417. Wilkie, A. 0. M. (1990) Genomics 7, 195-206. 32. Morton, N. E. & Andrews, V. (1989) Ann. Hum. Genet. 53, 16. Germino, G. G. G., Barton, N. J., Lamb, J., Higgs, D. R., 263-269. Harris, P., Xiao, G. H., Scherer, G., Nakamura, Y. & Reeders, 33. Morton, N. E. & Collins, A. (1990) Ann. Hum. Genet. 54, S. T. (1990) Am. J. Hum. Genet. 46, 925-933. 235-251. 17. Himmelbauer, H., Reeders, S. T., Ceccherini, I., Romeo, G. & 34. Morton, N. E. (1991) Proc. Natl. Acad. Sci. USA 88, 7474- Frischauf, A. M. (1989) Cytogenet. Cell Genet. 51, 1014 (ab- 7476. str.). 35. Francke, U. & Oliver, N. (1978) Hum. Genet. 45, 137-165. 18. Breuning, M. H., Snijdewint, F. G. M., Brunner, H., Verwest, 36. Chen, L. Z., Harris, P. C., Apostolou, S., Baker, E., Kolman, A., Ijdo, J. W., Saris, J. J., Dauwerse, J. G., Blondel, L. A. J., K., Lane, S. A., Nancarrow, J. K., Whitmore, S. A., Stallings, Keith, T., Callen, D. F., Hyland, V. J., Xiao, H. G., Scherer, R. L., Hildebrand, C. E., Richards, R. I., Sutherland, G. R. & G., Higgs, D. R., Harris, P., Bachner, L., Reeders, S. T., Callen, D. F. (1991) Genomics 10, 308-312. Germino, G., Pearson, P. L. & van Ommen, G. J. B. (1990) J. 37. Keats, B. J. B., Ott, J. & Conneally, M. (1989) Cytogenet. Cell Med. Genet. 27, 603-613. Genet. 51, 459-502. 19. Hyland, V. J., Suthers, G. K., Friend, K., MacKinnon, R. N., 38. Keats, B. J. B., Sherman, S. L. & Ott, J. (1990) Cytogenet. Callen, D. F., Breuning, M. H., Keith, T., Brown, V. A., Cell Genet. 55, 387-394. Phipps, P. & Sutherland, G. R. (1990) Hum. Genet. 84, 286- 39. Reeders, S. T. & Hildebrand, C. E. (1989) Cytogenet. Cell 288. Genet. 51, 299-318. 20. Himmelbauer, H., Germino, G., Ceccherini, I., Romeo, G., 40. Wilkie, A. 0. M., Higgs, D. R., Rack, K. A., Buckle, V. J., Reeders, S. T. & Frischauf, A. M. (1991) Am. J. Hum. Genet. Spurr, N. K., Fischel-Ghodsian, N., Ceccherini, I., Brown, 48, 325-334. W. R. A. & Harris, P. C. (1991) Cell 64, 595-606. 21. Breuning, M. H., Reeders, S. T., Brunner, H., Ijdo, J.-W., 41. Dauwerse, J. G., Jumelet, E. A., Wessels, J. W., Mollenvan- Saris, J. J., Verwest, A., van Ommen, G. J. B. & Pearson, ger, P., Beverstock, G. C., Peters, D. J., Van Ommen, G.-J. B. P. L. (1987) Lancet ii, 1359-1361. & Breuning, M. H. (1991) Cytogenet. Cell Genet., in press. Downloaded by guest on October 1, 2021