R.P. Creagan

Localization of the human α-globin structural gene to chromosome 16 in somatic cell hybrids by molecular hybridization assay

Abstract We have used 16 human × mouse somatic cell hybrids containing a variable number of human chromosomes to demonstrate that the human α-globin gene is on chromosome 16. Globin gene sequences were detected by annealing purified human α-globin complementary DNA to DNA extracted from hybrid cells. Human and mouse chromosomes were distinguished by Hoechst fluorescent centromeric banding, and the individual human chromosomes were identified in the same spreads by Giemsa trypsin banding. Isozyme markers for 17 different human chromosomes were also tested in the 16 clones which have been characterized. The absence of chromosomal translocation in all hybrid clones strongly positive for the α-globin gene was established by differential staining of mouse and human chromosomes with Giemsa 11 staining. The presence of human chromosomes in hybrid cell clones which were devoid of human α-globin genes served to exclude all human chromosomes except 6, 9, 14 and 16. Among the clones negative for human α-globin sequences, one contained chromosome 2 (JFA 14a 5), three contained chromosome 4 (AHA 16E, AHA 3D and WAV R4D) and two contained chromosome 5 (AHA 16E and JFA14a 13 5) in >10% of metaphase spreads. These data excluded human chromosomes 2, 4 and 5 which had been suggested by other investigators to contain human globin genes. Only chromosome 16 was present in each one of the three hybrid cell clones found to be strongly positive for the human α-globin gene. Two clones (WAIV A and WAV) positive for the human α-globin gene and chromosome 16 were counter-selected in medium which kills cells retaining chromosome 16. In each case, the resulting hybrid populations lacked both human chromosome 16 and the α-globin gene. These studies establish the localization of the human α-globin gene to chromosome 16 and represent the first assignment of a nonexpressed unique gene by direct detection of its DNA sequences in somatic cell hybrids.

Somatic Cell Genetic Assignment of Peptidase C and the Rh Linkage Group to Chromosome A-1 in Man

The segregation of the human peptidase-C phenotype in five different series of human-mouse hybrid clones was examined. The chromosome constitution of these hybrids was determined by quinacrine mustard fluorescence, Giemsa banding, and constitutive heterochromatin staining. That the clones could be classified without exception either as human peptidase C positive/ A-1 positive (14 clones), or as peptidase C negative/ A-1 negative (12 clones) indicates that peptidase C can be assigned to the human A-i chromosome. Data from an extensive series of human-mouse clones used provide support for the syntenic association between peptidase C and phosphoglucomutase-1 and by inference a linkage of both to Rh factor group.

Chromosome assignments of genes in man using mouse-human somatic cell hybrids: Mitochondrial superoxide dismutase (indophenol oxidase-B, tetrameric) to chromosome 6

SummaryEvidence from mouse/human somatic cell hybrids is presented for the synteny of the genes for indophenol oxidase-B (tetrameric) and cytoplasmic malic enzyme (EC 1.1.1.40). Assignment of these two genes to chromosome 6 is further confirmed. The identification of indophenol oxidase-B (tetrameric) as mitochondrial superoxide dismutase is discussed.ZusammenfassungBefunde an somatischen Zellhybriden Maus/Mensch werden dargestellt, die für die Syntenie der Gene für Indophenol-Oxidase-B (tetramer) sowie für cytoplasmatisches malic enzyme (EC 1.1.1.40) sprechen. Außerdem wird die Zuordnung dieser beiden Gene zu Chromosom 6 bestätigt. Die Identifizierung der Indophenol-Oxidase-B (tetramer) als mitochondriale Superoxid-Dismutase wird diskutiert.

Chromosome Assignments in Man of the Genes for Two Hexosephosphate Isomerases

Thirty-seven clones of somatic cell hybrids between human and mouse cells were examined for retention of human chromosomes and expression of human constitutive enzymes. Human glucosephosphate isomerase and chromosome F-19 were retained or lost concordantly, as were human mannosephosphate isomerase and chromosome C-7. The genes for the enzymes are thus assigned to these two chromosomes.

Assignment of the genes for human peptidase A to chromosome 18 and cytoplasmic glutamic oxaloacetate transaminase to chromosome 10 using somatic-cell hybrids

Evidence based on analysis of mouse-human somatic-cell hybrids is presented that supports the assignment for the structural loci of peptidase A to human chromosome 18 and of cytoplasmic glutamate oxaloacetate transaminase (GOT) (EC 2.6.1.1) to chromosome 10. The medical and evolutionary significance of these assignments is discussed.

Genetic Homology between Man and the Chimpanzee: Syntenic Relationships of Genes for Galactokinase and Thymidine Kinase and Adenovirus-12-Induced Gaps using Chimpanzee-Mouse Somatic Cell Hybrids

The induction by adenovirus-12 of a site-specific gap and assignment of the chimpanzee genes for thymidine kinase and galactokinase were studied by utilizing chimpanzee-mouse hybrid cells. It has been shown that adenovirus-12 induces a specific gap in the long arm of human chromosome 17 (HS 17); with chimpanzee-mouse hybrid cells the specific gap appears on the short arm of the chimpanzee homolog [PTR 19 (HS 17)] of HS 17. This result supports the proposed relationship of HS 17 to PTR 19 (HS 17) by means of a pericentric inversion. The chimpanzee thymidine kinase and galactokinase genes were assigned to PTR 19 (HS 17), further confirming the homology to HS 17. Other syntenic relationships and gene assignments were consistent with proposed homologies between chimpanzee and human chromosomes.