Cytogenet. Cell Genet. 22: 598-601 (1978)
Chimpanzee chromosome 13 is homologous to human chromosome arm 2p N.C. Sun , C.R.Y. S un , and T. Ho Biology Division, Oak Ridge National Laboratory, Oak Ridge, Tenn.
Supported by the Energy Research and Development Administration under contract with the Union Carbide Corporation.
Downloaded by: Washington University 128.252.67.66 - 5/14/2018 11:29:14 AM
Karyotypic studies have well established that the chimpanzee (Pan troglodytes) has 48 chromosomes and the human 46. However, the banding patterns of most human chromosomes are extremely similar to those of the chimpanzee’s, except for human chromosome 2, which does not have a counterpart in the chimpanzee. The differences between the chim panzee and human karyotypes, as revealed by various banding techniques, have been interpreted as involving a centric fusion of two chimpanzee acrocentric chromosomes to form human chromosome 2, four pericentric inversions in human chromosomes 4, 5, 12, and 17, and the acquisition of centromeric constrictions in human chromosomes 1 and 19.' The two pairs of chimpanzee chromosomes which appear by their banding patterns to be homologous to the human chromosome arms 2p and 2q have been suggested as the chimpanzee chromosomes 12 and 13, respectively.2 In the (Is 4- Is) interspecific hybrid between the human lymphoblastoid cell and the galactose-negative mutant, Gal-2, of Chinese hamster origin, a single human chromosome 2 is retained preferentially because the Gal*-Act gene, or the gene for NADH-coenzyme Q reductase, is located on human chromosome arm 2p, which complements the defec tiveness of the Gal-2 mutant.3-4 The proposed homologies of human chromosome arm 2p and the chimpanzee chromosome 12 can be tested by fusing Gal-2 mutant cells with chimpanzee cells and determining which chimpanzee chromosome is preferentially retained.
Sun et al.
Comparative mapping of gene loci
599
Cell hybrids were obtained from the chimpanzee lymphocyte cell LE-7 and the Chinese hamster mutant cell Gal-2. Galactose medium selects against Gal-2 cells, while LE-7 cells can be removed by medium changes. Three independent primary hybrid clones were isolated. Karyotype analyses were performed after G-banding. An average of 15 karyotypes was studied for each hybrid and subclone. Extracts obtained from these hybrids and subclones were analyzed by starch-gel electrophoresis for acid phosphatase 1 (ACP,, E.C. 3.1.3.2), NAD-dependent cyto plasmic malate dehydrogenase (MDHS, E.C. 1.1.1.37), and galactose-1-phosphate uridylyltransferase (GALT, E.C. 2.7.7.12). The chimpanzee form of IDHS (E.C. 1.1.1.42) can not be separated from the Chinese hamster form in our electrophoresis system.
The three primary chimpanzee-Chinese hamster hybrid clones were analyzed for isozymes, ACPi, MDH*, and GALT, and for chromosome complements (table I). The chimpanzee chromosome 13 among others was always retained in these three primary hybrids maintained in the selective medium. They also expressed both the Chinese hamster and the chimpanzee forms of ACPi and MDHS. However, the chimpanzee form of GALT was expressed only in two hybrid clones, GC-4 and GC-14, but not in GC-1, indicating its lack of syntenic relationship with the ACPi and MDHs markers. Expression of chimpanzee Gal+-Act in all three hybrids was inferred from their ability to grow in galactose medium. One of the three hybrids, GC-1, was backselected in glucose medium to study the relationship between the presence of chimpanzee chromo some 13 and the concordant expression of ACPi, MDHs, and Gal+-Act. In the 20 galactose-positive subclones able to grow in galactose medium,
Table I. The karyotypic and isozymic characteristics of chimpanzee-Chinese hamster hybrid clones. Genomic constitution of hybrids
Expression of chimpanzee forms of isozymes ACP,
MDHS GALT
GC-1
2s + Is
+
+
GC-4
3s + Is
+
+
+
GC-14
2s + Is
+
+
+
Presence of chimpanzee chromosomes
1, 3, 9, 10, 11, 13, 15, 16, 17, 19, 20, 21, 22, Y 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, X, Y 2, 3, 5, 9, 10, 11, 12, 13, 16, 19, 20, 21, 23, X Downloaded by: Washington University 128.252.67.66 - 5/14/2018 11:29:14 AM
Hybrid designation
Sun et al. Comparative mapping of gene loci
600
Table II. Assignment of the genes for G al+-Act, MDHg, and ACP! to chromo some 13 in the chimpanzee. Hybrid GC-1 and subclones
Expression of chimpanzee gene loci Gal*-Act
MDHS
ACP,
Presence of chimpanzee chromosome 13
GC-1 Galactose-positive subclones 1 through 20 Galactose-negative subclones 21 through 30
+ +
+ +
+ +
+ +
-
-
-
-
■
the chimpanzee forms of ACPi, MDH.s, and Gal+-Act were expressed; however, the 10 galactose-negative subclones unable to grow in galactose medium did not express the chimpanzee forms of ACPi, MDHs, and Gal+-Act (table II). As a result, the ACPi, MDHs, and Gal*-Act genes can be assigned to chimpanzee chromosome 13. Since these genes have been assigned to human chromosome arm 2p, we suggest that the chim panzee chromosome 13 is homologous to human chromosome arm 2p.34 Our result is corroborated by the data reported by Pearson et al.5* but differs from the proposal of the P aris C onference (1971), S upplement (1971 5)2 and the hypothesis of de G rouchy et al.G-7
2
3
4
5
de G rouchy, J., and K lein, M.: Phylogénie chromosomique de l'homme et des primates hominiens (Pan troglodytes, Gorilla gorilla et Pongo pygmaeus): essai de reconstitution du caryotype de l’ancêtre commun. Annls Génét. 15: 225-240 (1972). P aris Conference (1971), Supplement (1975): Standardization in human cyto genetics. Birth defects: Original Article Series, Vol. 11, No. 9 (The National Foundation, New York 1975). C hu, E.H.Y.; C hang, C.C., and Sun, N.C.: Synteny of the human genes for Gal-l-PT, ACP[, MDH-1, and G al+-Act and assignment to chromosome 2. Rotterdam Conference (1974), pp. 103-106. D eF rancesco, L.; Scheffler, I.E., and Bissell, M.J.: A respiration-deficient Chinese hamster cell line with a defect in NADH-coenzyme Q reductase. J. biol. Chem. 251: 4588-4595 (1976). P earson, P.L.; G arver, J.J.; E stop, A.; D ijksman, T.M.; W ijnen, L.M.M., and M eera K han, P.: Gene assignments to the presumptive homologs of human
Downloaded by: Washington University 128.252.67.66 - 5/14/2018 11:29:14 AM
1 T urleau, C.;
Sun et al. Comparative mapping of gene loci
601
Downloaded by: Washington University 128.252.67.66 - 5/14/2018 11:29:14 AM
chromosomes 2, 9, 13, 14, and 15 in the Pongidae and Cercopithecoidae. This conference (1977). 6 de G rouchy, J.; T urleau, C.; Roubin, M., and K lein , M.: Evolutions caryotypiques de l’homme et du chimpanzé: étude comparative des topographies bandes après dénaturation ménagée. Annls Génét. 15: 79-84 (1972). 7 de G rouchy, J.; T urleau, C.; Roubin, M., and C olin, F.C.: Chromosomal evolution of man and the primates (Pan troglodytes, Gorilla gorilla, Pongo pygmaeus). Nobel Symp. 23: 124-131 (1973).
Chimpanzee chromosome 13 is homologous to human chromosome arm 2p N.C. Sun , C.R.Y. S un , and T. Ho Biology Division, Oak Ridge National Laboratory, Oak Ridge, Tenn.
Supported by the Energy Research and Development Administration under contract with the Union Carbide Corporation.
Downloaded by: Washington University 128.252.67.66 - 5/14/2018 11:29:14 AM
Karyotypic studies have well established that the chimpanzee (Pan troglodytes) has 48 chromosomes and the human 46. However, the banding patterns of most human chromosomes are extremely similar to those of the chimpanzee’s, except for human chromosome 2, which does not have a counterpart in the chimpanzee. The differences between the chim panzee and human karyotypes, as revealed by various banding techniques, have been interpreted as involving a centric fusion of two chimpanzee acrocentric chromosomes to form human chromosome 2, four pericentric inversions in human chromosomes 4, 5, 12, and 17, and the acquisition of centromeric constrictions in human chromosomes 1 and 19.' The two pairs of chimpanzee chromosomes which appear by their banding patterns to be homologous to the human chromosome arms 2p and 2q have been suggested as the chimpanzee chromosomes 12 and 13, respectively.2 In the (Is 4- Is) interspecific hybrid between the human lymphoblastoid cell and the galactose-negative mutant, Gal-2, of Chinese hamster origin, a single human chromosome 2 is retained preferentially because the Gal*-Act gene, or the gene for NADH-coenzyme Q reductase, is located on human chromosome arm 2p, which complements the defec tiveness of the Gal-2 mutant.3-4 The proposed homologies of human chromosome arm 2p and the chimpanzee chromosome 12 can be tested by fusing Gal-2 mutant cells with chimpanzee cells and determining which chimpanzee chromosome is preferentially retained.
Sun et al.
Comparative mapping of gene loci
599
Cell hybrids were obtained from the chimpanzee lymphocyte cell LE-7 and the Chinese hamster mutant cell Gal-2. Galactose medium selects against Gal-2 cells, while LE-7 cells can be removed by medium changes. Three independent primary hybrid clones were isolated. Karyotype analyses were performed after G-banding. An average of 15 karyotypes was studied for each hybrid and subclone. Extracts obtained from these hybrids and subclones were analyzed by starch-gel electrophoresis for acid phosphatase 1 (ACP,, E.C. 3.1.3.2), NAD-dependent cyto plasmic malate dehydrogenase (MDHS, E.C. 1.1.1.37), and galactose-1-phosphate uridylyltransferase (GALT, E.C. 2.7.7.12). The chimpanzee form of IDHS (E.C. 1.1.1.42) can not be separated from the Chinese hamster form in our electrophoresis system.
The three primary chimpanzee-Chinese hamster hybrid clones were analyzed for isozymes, ACPi, MDH*, and GALT, and for chromosome complements (table I). The chimpanzee chromosome 13 among others was always retained in these three primary hybrids maintained in the selective medium. They also expressed both the Chinese hamster and the chimpanzee forms of ACPi and MDHS. However, the chimpanzee form of GALT was expressed only in two hybrid clones, GC-4 and GC-14, but not in GC-1, indicating its lack of syntenic relationship with the ACPi and MDHs markers. Expression of chimpanzee Gal+-Act in all three hybrids was inferred from their ability to grow in galactose medium. One of the three hybrids, GC-1, was backselected in glucose medium to study the relationship between the presence of chimpanzee chromo some 13 and the concordant expression of ACPi, MDHs, and Gal+-Act. In the 20 galactose-positive subclones able to grow in galactose medium,
Table I. The karyotypic and isozymic characteristics of chimpanzee-Chinese hamster hybrid clones. Genomic constitution of hybrids
Expression of chimpanzee forms of isozymes ACP,
MDHS GALT
GC-1
2s + Is
+
+
GC-4
3s + Is
+
+
+
GC-14
2s + Is
+
+
+
Presence of chimpanzee chromosomes
1, 3, 9, 10, 11, 13, 15, 16, 17, 19, 20, 21, 22, Y 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, X, Y 2, 3, 5, 9, 10, 11, 12, 13, 16, 19, 20, 21, 23, X Downloaded by: Washington University 128.252.67.66 - 5/14/2018 11:29:14 AM
Hybrid designation
Sun et al. Comparative mapping of gene loci
600
Table II. Assignment of the genes for G al+-Act, MDHg, and ACP! to chromo some 13 in the chimpanzee. Hybrid GC-1 and subclones
Expression of chimpanzee gene loci Gal*-Act
MDHS
ACP,
Presence of chimpanzee chromosome 13
GC-1 Galactose-positive subclones 1 through 20 Galactose-negative subclones 21 through 30
+ +
+ +
+ +
+ +
-
-
-
-
■
the chimpanzee forms of ACPi, MDH.s, and Gal+-Act were expressed; however, the 10 galactose-negative subclones unable to grow in galactose medium did not express the chimpanzee forms of ACPi, MDHs, and Gal+-Act (table II). As a result, the ACPi, MDHs, and Gal*-Act genes can be assigned to chimpanzee chromosome 13. Since these genes have been assigned to human chromosome arm 2p, we suggest that the chim panzee chromosome 13 is homologous to human chromosome arm 2p.34 Our result is corroborated by the data reported by Pearson et al.5* but differs from the proposal of the P aris C onference (1971), S upplement (1971 5)2 and the hypothesis of de G rouchy et al.G-7
2
3
4
5
de G rouchy, J., and K lein, M.: Phylogénie chromosomique de l'homme et des primates hominiens (Pan troglodytes, Gorilla gorilla et Pongo pygmaeus): essai de reconstitution du caryotype de l’ancêtre commun. Annls Génét. 15: 225-240 (1972). P aris Conference (1971), Supplement (1975): Standardization in human cyto genetics. Birth defects: Original Article Series, Vol. 11, No. 9 (The National Foundation, New York 1975). C hu, E.H.Y.; C hang, C.C., and Sun, N.C.: Synteny of the human genes for Gal-l-PT, ACP[, MDH-1, and G al+-Act and assignment to chromosome 2. Rotterdam Conference (1974), pp. 103-106. D eF rancesco, L.; Scheffler, I.E., and Bissell, M.J.: A respiration-deficient Chinese hamster cell line with a defect in NADH-coenzyme Q reductase. J. biol. Chem. 251: 4588-4595 (1976). P earson, P.L.; G arver, J.J.; E stop, A.; D ijksman, T.M.; W ijnen, L.M.M., and M eera K han, P.: Gene assignments to the presumptive homologs of human
Downloaded by: Washington University 128.252.67.66 - 5/14/2018 11:29:14 AM
1 T urleau, C.;
Sun et al. Comparative mapping of gene loci
601
Downloaded by: Washington University 128.252.67.66 - 5/14/2018 11:29:14 AM
chromosomes 2, 9, 13, 14, and 15 in the Pongidae and Cercopithecoidae. This conference (1977). 6 de G rouchy, J.; T urleau, C.; Roubin, M., and K lein , M.: Evolutions caryotypiques de l’homme et du chimpanzé: étude comparative des topographies bandes après dénaturation ménagée. Annls Génét. 15: 79-84 (1972). 7 de G rouchy, J.; T urleau, C.; Roubin, M., and C olin, F.C.: Chromosomal evolution of man and the primates (Pan troglodytes, Gorilla gorilla, Pongo pygmaeus). Nobel Symp. 23: 124-131 (1973).
