AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 86:81-84 11991) Brief Report: Cytogenetic Study of Hapalemur aureus Y. RUMPLER, S. WARTER, M. HAUWY, V. RANDRIANASOLO, AND B. DUTRILLAUX Uniuersite Louis Pusteur, Faculte de Medecine, Institut d’Embryologie, F-67085 Strusbourg, France KEY WORDS Chromosomal evolution, Prosimian, Lemuridae ABSTRACT The karyotype of Hapalemur aureus was compared with those of other Hapalemur species, allowing us to determine the phylogenetic position of this species on the evolutionary tree of the Lemuridae. mur species indicates that Hapalemur karyotypes possess many identical acrocentric chromosomes and th a t two metacentric ones, corresponding to HGO 1and HGO 12 of H. griseus occidentalis and present in all the H.griseus, do not exist in H. aureus. They are replaced by acrocentric chromosomes (Fig. 3). Two explanations may be proposed: 1)the acrocentric chromosomes are ancestral chromosomes; 2) they derived by two rearrangements from HGO chromosomes, a centric fission splitting HGO 1into HAU 1and HAU 12 of H . aureus and a pericentric inversion (or a centromeric shift) transforming the submetacentric HGO 2 into a n acrocentric chromosome, HAU 2 (Fig. 3). In accordance with previous results, the second hypothesis appears the most probable. Indeed a comparative study of the karyotypes of most species of lemurs allowed us to reconstruct the ancestral karyotype of all the lemurs: LEM (Rumpler et al., 1983). It contains only acrocentric autosomes and is very similar to that MATERIALS AND METHODS of Cheirogaleidae (Rumpler and Dutrillaux, Lymphocyte cultures were prepared from 1979). On the trunk leading to the Lemua pair of H . aureus captured in the wild, as ridae a first robertsonian translocation bewere fibroblast cultures from a skin biopsy tween two ancestral chromosomes, LEM 10 specimen obtained from a male kept in the and LEM 24, gave rise to a small submetazoo of Tsimbazaza, in Antananarivo. R-band centric chromosome, HGO 2, common to all (RHG, RBA) and C-band (CBG)(ISCN, 1978) the species of Eulemur, Hapalemur, and Letechniques were applied on the chromosomal mur catta, except H . aureus (Fig. 4).A second preparations. robertsonian translocation between ancestral chromosomes LEM 1 and LEM 3 gave RESULTS AND DISCUSSION rise to chromosome 1 of L. catta (LCA I), The karyotype of H. aureus comprises 62 characterizing the branch leading to the L. chromosomes (Fig. 1).All pairs are acrocen- cattalHapalemur group, whereas on a lattric, including the sex chromosomes X and Y. C-banding exhibited the presence of large Received October 18,1990; accepted March 21,1991. heterochromatic segments on all juxtacenreprint requests to Professor Yves Rumpler, Univertromeric regions (Fig. 2). Comparison of the siteAddress Louis Pasteur, Faculte de Medecine, Institut d’Ernbryologie, karyotypes of H. aureus and other Hapale- 11rue Humann, 67085 Strasbourg Cedex, France When Hapalemur aureus was discovered in 1987 by Meier et al., it was classified as a new species essentially on the basis of morphological and ecological characters. A preliminary cytogenetic study of this species (Rumpleret al., 1988)revealedthat its karyotype did not differ from those of other Hapalemur through chromosomal rearrangements that would allow us to predict meiotic disorders leading to sterility of hybrids (Ratomponirina et al., 1988). For these reasons the karyotype of H . aureus was not published in the previous paper. However, karyotype comparisons of all the other species of gentle lemurs (Rumpler and Dutrillaux, 1978; Warter et al., 1987)allowed us to construct a phylogenetic tree of this group, and it appeared important to carry out a comparative study of the karyotypes of all the Hapalemur species in order to locate the point of emergence of H . aureus from this evolutionary tree. @ 1991 WILEY-LISS, INC 82 Y.RUMPLER ET AL. Fig. 2. C-banded karyotype o f Hapalemur aureus showing juxtacentromeric heterochromatin on all chromosomes. Fig. 1. R-banded karyotype OfHapalemuraureus.All chromosomes are acrocentric. era1 branch leading to Eulemur species another robertsonian translocation occurred between the ancestral chromosomes LEM 1 and LEM 13. The chromosome LCA 1 was then modified by a centromeric shift giving rise to HSI 1, and a new inversion of HSI 1 gave rise to chromosome HGO 1(Simons and Rumpler, 1988). Thus the ancestral karyotype of all the H. HAU 1 2 HGO 2 HGO 1 HAU 2 HAU 1 Fig. 3. Chromosomal rearrangements that occurred on ancestral chromosomes 1 and 2 of Hapalemurgriseus in order to give rise to chromosomes 1, 2, and 12 of Hapalemur aureus. h, Juxtacentromeric chromatin. 83 CYTOGENETIC STUDY OF H. AUREUS H S I 1- HGO 1 LCA 1 e H S I 1 LEM LEM 1 4 3 4 L C A 1 Fig. 4. Phylogenetic tree of the chromosomal evolution of Lemur catta and the different species of Hapalemur. Branches that end with arrows and lead to Eulemur, LCA, and HSI do not bear all the rearrangements that occurred, whereas on those leading to Hapalemur aureus and to the different species of Hapalemur all the chromosomal rearrangements have been reported. LCA, Lemur catta; HSI, Hapalemur simus; HAU, H. aureus; HGO, H . griseus occidentalis; HGS, H. g. ssp; HGM, H . g. meridionalis; HGG,H.g.griseus; HGA, H.g. alaotrensis, LEM, ancestral karyotype of all the lemurs; asterisks, gain of hetrochromatin; arrows, centromeric fissions; closed circles, shifts; open circles, pericentric inversions. griseus contained these two submetacentric ical evidence, the cytogenetic data showing a chromosomes HGO 1 and HGO 2, which short common trunk for H. aureus and H. were rearranged by a fission and a centro- griseus support the view that H. aureus is meric shift (or pericentric inversion), leading closer to H . griseus than to H . simus. It has been previously reported that chromoto the specific chromsomes HAU 1,HAU 12 somal evolution of the Lemuridae occurred of H. aureus. Another argument against the first hy- chiefly by robertsonian translocations, expothesis, according to which these three cept for the group L. cattalHapalemur,which chromsomes would have been ancestral also underwent pericentric inversions (Rumcones, is that their banding pattern cor- pler and Dutrillaux, 1978). In this sense, the responds to acrocentrics of neither other Le- evolution of H. aureus follows the trend seen mur species nor the ancestral karyotype elsewhere in this group. Our data also reinforce the findings that the rare non-robertsoLEM. Our data allow us to determine precisely nian chromosomal rearrangements t h a t octhe phylogenetic position of H. aureus in curred during the Lemuridae evolution relation to the other Hapalemur previously always involved the same chromosomes: the studied. It emerged from the trunk leading ancestral chromosomes 1 and 2 and their to H. griseus after the formation of the karyo- derivatives, in addition to the X chromotype ofH. simus (Fig. 3). Like the morpholog- some. 84 Y. RUMPLER ET AL ACKNOWLEDGMENTS We thank the Zoo of Tsimbazaza in Antananarivo for permitting the skin biopsy. We are grateful to Mrs. Lombard and Mr. H. Hauwy for technical assistance, Mr. G. Cadiou for photographic work, and Mrs. M. Lavaux for secretarial assistance. Thanks are also due to Mr. J. Anderson for reviewing the English version of the manuscript. LITERATURE CITED ISCN (1978) An international system for chromosome nomenclature. Cytogenet. Cell Genet. 21t309-404. Meier B, Albignac R, Peyrieras A, Rumpler Y, and Wright P (1987) A new species of Hapalemur (Primates) from South East Madagascar. Folia Primatol. 48:211-215. Ratomponirina C, Brun B, and Rumpler Y (1988) Synaptonemal complexes in robertsonian translocation heterozygous in lemurs. In PE Brandham (ed): Kew Chromosome. London: H.M.S.O., pp. 65-73. Rumpler Y, Couturier J, Warter S, Dutrillaux B (1983) Chromosomal evolution in Malagasy lemurs. VII. Phylogenic relationships between Propithecus, Auahi (Indriidae), Microcebus (Cheirogaleidae)and Lemur (Lemuridae). Cytognet. Cell Genet. 36.542-546. Rumpler Y, and Dutrillaux B (1978) Chromosomal evolution in Malagasy lemurs. 111. Chromosome banding studies in the genus Hapalemur and the species Lemur catta. Cytogenet. Cell Genet. 21t201-211. Rumpler Y, and Dutrillaux B (1979) Chromosomal evolution in Malagasy lemurs. IV.Chromosome banding studies in the genuses Phaner, Varecia, Lemur, Microcebus and Cheirogaleus. Cytogenet. Cell Genet. 24t224-232. Rumpler Y, Meier B, and Rakotosamimanana B (1988) La decouverte d u n nouveau Primate. La Recherche 202t1092-1094. Simons E, Rumpler Y (1988) Eulemur: New generic name for species of Lemur other than Lemur catta. C.R. Acad. Sci. Paris 307t547-551. Warter S, Randrianasolo G, Dutrillaux B, and Rumpler Y (1987) Cytogenetic study of a new subspecies of Hapalemur griseus. Folia Primatol. 48.50-55.