J. Zool., Lond. (1973) 169, 403--407 Chromosomes of Gorilla gorilla gorilla MARY LUCAS AND ISOBEL WALLACE The Galton Laboratory, Universitjj College, London (Accepted 14 November 1972) (With 4 plates in the text) Chromosome preparations from four gorillas have been examined by conventional tech- niques. In two of the specimens banding patterns have been shown by special staining techniques, and compared with the pattern found in human chromosomes. Introduction Several reports (Hamerton et al., 1961 ; Hamerton et al., 1963; Egozcue & Chiarelli, 1967) have described the karyotype of the gorilla although specimens from only a few animals have been examined. This report describes the karyotype of four animals, and the banding patterns of two of them. Materials and methods The chromosome preparations were obtained from peripheral blood cultures. When the animals were anaesthetized venous blood was taken and in three cases placed in heparin; un- fortunately in one case (N’Pongo) only clotted blood was available. The cultures were set up by a modification of published methods as routinely used for human bIood (Moorhead et al., 1960, Hirschhorn, 1965); mini method for “Lomi” and “Guy” and the micro method for “Nandi” and “N’Pongo”. Cultures were set up using human and foetal calf serum in the medium. Many mitoses were obtained with both types of serum, but more satisfactory chromosome spreads were obtained from the cultures enriched with human serum. The greatest number of mitoses appeared in cultures harvested after 80 h. Slides from all 4 specimens were stained with orcein. Preparations from “Nandi” and “Guy” were banded by an adaptation of the trypsinization method of Seabright (Lucas, Wallace & Hirschhorn, 1972). Results As shown in Table 1 all four animals had a chromosome number of 48. Karyotypes were constructed from photomicrographs of cells from all four animals. The arrangement shown in Plate I was found in the three females. The largest chromosomes were 11 pairs of metacentrics or submetacentrics. There were five pairs of large acrocentrics. In descend- ing order of size there were then four pairs which could be separated into two groups in most cells. Two pairs are metacentric; one of these pairs sometimes showed a secondary 403
Transcript
J. Zool., Lond. (1973) 169, 403--407
Chromosomes of Gorilla gorilla gorilla
MARY L U C A S A N D ISOBEL W A L L A C E The Galton Laboratory, Universitjj College, London
(Accepted 14 November 1972)
(With 4 plates in the text)
Chromosome preparations from four gorillas have been examined by conventional tech- niques. In two of the specimens banding patterns have been shown by special staining techniques, and compared with the pattern found in human chromosomes.
Introduction Several reports (Hamerton et al., 1961 ; Hamerton et al., 1963; Egozcue & Chiarelli,
1967) have described the karyotype of the gorilla although specimens from only a few animals have been examined. This report describes the karyotype of four animals, and the banding patterns of two of them.
Materials and methods The chromosome preparations were obtained from peripheral blood cultures. When the
animals were anaesthetized venous blood was taken and in three cases placed in heparin; un- fortunately in one case (N’Pongo) only clotted blood was available. The cultures were set up by a modification of published methods as routinely used for human bIood (Moorhead et al., 1960, Hirschhorn, 1965); mini method for “Lomi” and “Guy” and the micro method for “Nandi” and “N’Pongo”. Cultures were set up using human and foetal calf serum in the medium. Many mitoses were obtained with both types of serum, but more satisfactory chromosome spreads were obtained from the cultures enriched with human serum. The greatest number of mitoses appeared in cultures harvested after 80 h.
Slides from all 4 specimens were stained with orcein. Preparations from “Nandi” and “Guy” were banded by an adaptation of the trypsinization method of Seabright (Lucas, Wallace & Hirschhorn, 1972).
Results As shown in Table 1 all four animals had a chromosome number of 48. Karyotypes were
constructed from photomicrographs of cells from all four animals. The arrangement shown in Plate I was found in the three females. The largest chromosomes were 11 pairs of metacentrics or submetacentrics. There were five pairs of large acrocentrics. In descend- ing order of size there were then four pairs which could be separated into two groups in most cells. Two pairs are metacentric; one of these pairs sometimes showed a secondary
403
404 M. LUCAS A N D I . WALLACE
constriction, but this was only obvious in a few cells. The other two pairs were sub- metacentric. Two pairs of small metacentric chromosomes were easily distinguished. The smallest chromosomes were two pairs of acrocentrics which were satellited.
Number of cells examined with the incidence of satellite association and cells with aberraiions
No. of cells with No. of cells No. of small No. of large No. of cells chromosome no. showing satellite acrocentrics acrocentrics with an 47 48 49 association seen in S/A seen in S/A aberration
( )* Number of times “marker” small acrocentric with large satellites seen in association.
CHROMOSOMES O F G. G. G O R I L L A 405
The male karyotype showed 21 large chromosomes. The Y was submetacentric and slightly larger than the small acrocentrics. On a slide stained with quinacrine hydrochloride and viewed with incident ultraviolet light, the long arms of the Y showed brilliant fluores- cence, similar to that reported by Pearson et al. (1971).
In every mitosis examined from Guy one of the large acrocentrics was easily distinguished because it was smaller than the other nine. This difference in size appeared to be due to the absence of satellites, this chromosome having only very small short arms (Plate 11). The
A Lomi
N' Pongo 3t
A x Nondi
PLATE I I . (a) Guy; large acrocentrics of two cells. (b) Small acrocentrics of four specimens. One acrocentric in Lomi and N'Pongo with large satellite$.
406 M. LUCAS A N D I. WALLACE
banding, described below, did not give any indication that a translocation was present. There appears to be wide variation in the size of the satellites in this species. In the cells
of both Lomi and N’Pongo, one of the small acrocentrics had very large satellites. This chromosome could be easily identified in all the cells examined (Plate 11). Satellite associa- tion was frequently seen between the small acrocentrics but the large acrocentrics were seldom seen in association (see Table I).
After treatment with trypsin and Giemsa staining, clear banding patterns were seen in cells of Nandi. Using photomicrographs, it was possible to pair all the chromosomes (Plate 111). In several pairs the banding patterns closely resembled those seen in human
t
U -... PLATE 111. Karyotype of female gorilla (Nandi). Banding patterns after trypsinisation and Giemsa staining
Inset: male gorilla, sex chromosomes.
chromosomes (Plate 1V). The banding pattern on one pair of large submetacentrics was similar to that seen on the human X chromosome. When the banding patterns of Guy were examined, only one chromosome of the group of large chromosomes showed this pattern (Plate IV), which has therefore been placed as the X chromosome.
Other workers (Hamerton et al., 1963) have described similarities between the karyotype of the gorilla and that of man. These similarities are even more strikingly demonstrated when the chromosomes are examined after special staining.
C H R O M O S O M E S O F G . G . G O R I L L A 407
c
H 6 G H 7 G 1 J L 1
I H 13 G G I
PLATE IV. Human and gorilla chromosomes which show similar handing patterns. H, Human; G, gorilla.
We are very grateful to Dr Hawkey of the Nuffield Institute of Comparative Medicine, Zoolog- ical Society of London for the specimens from “Guy” and “Lomi”, and to Mr Jeremy Mallinson of the Jersey Wildlife Preservation Trust for the specimens from “Nandi” and “N’Pongo”.
Isobel Wallace is grateful to the M.R.C. for a Research Grant.
R E F E R E N C E S Egozcue, J. & Chiarelli, B. (1967). The rdiogram of the lowland gorilla. Foliuprimatol. 5 : 237-240. Hamerton, J. L. Fraccaro, M., de Carli, L., Nuzzo, F., Klinger, H. P. Hulliger, L., Taylor, A. & Lang, E. M.
(1961). Somaticchromosomes of the gorilla. Nature, Lond. 192: 225-228. Hamerton, J. L., Klinger, H. P., Mutton, D. E. & Lang, E. M. (1963). The somatic chromosomes of the Homino-
idea. Cytogenetics 2: 240-263. Hirschhorn, K. (1965). Method for studying lymphocyte interactions and other immunologic and cytogenic studies
of human lymphocytes. In Histocompatibility testing: Part 2. Methods: 177-178. Russell, P. S. & Winn, H. J. (Eds) National Academy of Sciences-National Research Council Publications No. 1229. Washington.
Moorhead, P. S., Nowell, P. C., Mellman, W. J. , Batipps, D. M. & Hungerford, D. A. (1960). Chromosome preparations of Ieucocytes cultured from human periferal blood. Exp/ Cell Res. 20: 613-61 6 .
Pearson, P. L., Bobrow, M., Vosa, C. <i. & Barlow, P. W. (1971). Quinacrinefluorescence in mammalian chromo- somes. Nature, Lond. 231: 326-329.
