Genes Genet. Syst. (1998) 73, p. 135–136 NOTES Comparative mapping of the Cri du Chat and DiGeorge syndrome regions in the great apes Sima T. Tarazami, Andrew M. Kringstein, Robert A. Conte, and Ram S. Verma Division of Genetics, The Long Island College Hospital, and Institute of Molecular Biology and Genetics, SUNY Health Science Center at Brooklyn, N.Y. 11228, U.S.A. (Received 29 December 1997, accepted 9 March 1998) Structural variations between great ape and human chromosomes due to pericentric inversions and translocations have created at apparent controversy during the re- construction of hominoid phylogeny. One such variation involves human chromo- some 5, which is equivalent to chromosome 4 in chimpanzee and orangutan but equiva- lent to segments of chromosomes 4 and 19 in gorilla. Obviously, neither banding patterns nor centromeric indecies in these chromosomes match. The pathological condition of cri du chat syndrome is due to the cytogenetic deletion of band p15. 2 of chromosome 5. Is this region involved during pericentric inversion of apes chromsome 4? We used a human cosmid probe for cri du chat syndrome as a phylogenetic marker in search of the aforementioned question. The genomic sequences for cri du chat syndrome region were conserved in chimpanzee (PTR4) and orangutan (PPY4) but displayed a positional divergence in gorilla on chromosome 19(GGO19). In addi- tion, we used a human cosmid DNA probe for DiGeorge syndrome which is located on chromosome 22 band q11.2 and was conserved within band 23q11.2 in apes. The loci specific human genomic probes may help to describe the inversions and translo- cations for other chromsomes. The banding patterns of human and great ape chromsomes probes for cri du chat (45 kb) and DiGeorge (35 kb) critical have been compared in constructing a phylogenetic tree regions to serve as evolutionary punctuation for the genomic (Yunis and Prakash, 1982; ISCN, 1985; Ibraimov, 1993). divergence/convergence of the phylogenetic tree. The chromosomal basis of human evolution has generated Great ape chromosomes: [chimpanzee (Pan troglodytes; controversies and henceforth the molecular approach has PTR), gorilla (Gorilla gorilla; GGO), and orangutan (Pongo become imperative (Caccone and Powell, 1989; Wienberg pygmaeus; PPY)] were prepared from fibrobalst cell lines et al., 1990; Ayala, 1995). Point mutations which have provided by NIGMG Human Genetic Mutant Cell reposi- accumulated during the evolutionary process have begun tory, Coriell Institute for Medical Research (Camden, New to dominate the scene, though anthropologists argues Jersey). against it (Verma and Luke, 1994). Metaphase chromosome spreads were obtained using the Recent availability of loci specific probes can serve as standard fibroblast harvesting procedure (Verma and Babu, genetic markers in describing the translocations and in- 1995). Human chromosomes were prepared from phyto- versions of apes genome (Luke and Verma, 1995). In hu- hemagglutinin (PHA) stimulated blood lymphocytes from man, a unique pathological condition termed cri du chat normal individuals. The FISH-technique by Pinkel et al., syndrome is generally caused by the cytogenetic deletion (1986) was used with minor modifications. For detecting of band p15.2 of chromosome 5 (Overbauser et al., 1994). the cri du chat (5p15.2) and DiGeorge (22q11.2) regions in Human chromosome 5 is equivalent to chromosome 4 of human and the great ape species, human biotin-labeled cri chimpanzee and orangutan and equivalent to segments of du chat and DiGeorge probes were used (Oncor, Gaithersberg, chromosomes 4 and 19 in gorilla (Stanyon et al., 1992). MD). Chromosomes were pre-identified by QFQ-banding Another dysmorphic feature noted in humans called techniques (ISCN, 1985). Twenty metaphases were ana- DiGeorge syndrome is due to the deletion of band q11.2 of lyzed from each experiment. chromosome 22 (Fibison et al., 1990). In the present Although, human chromsome 5 is equivalent to chimpan- investigation, we used two genomic unique DNA sequence zee and orangutan chromsome 4 and equivalent to segments 136 S. T. TARAZAMI et al. of gorilla chromosomes 4 and 19, neither the banding pat- terns of the ape chromosomes, nor the centrometric indicies match (ISCN, 1985). Despite such extreme divergence, which has obviously resulted due to pericentric inversions, the genomic sequences of cri du chat syndrome remain con- served at the expected position in chimpanzee and orangu- tan, but displayed diverged position in gorilla due to an apparent translocation (Fig. 1A and B). The structural variations in ape chromosomes can be viewed closely by using such genetic markers. Human chromsome 22 is equivalent to ape chromosomes 23 (Fig. 2A and B). The probe hybridized to 23q11.2 in ape chromsomes, suggesting that the DNA sequnce span- ning DiGeroge syndrme region is conservd. These results provide a convincing evidence that “highly specific se- quences” have been preserved during inversions and/or translocations. The structural variations of ape chromo- somes are being viewed here by using loci specific probes. REFERNECES Ayala, F. J. (1995) The myth of eve: Molecular biology and human origins. Science 270, 1930–1936. Caccone, A. and Powell, J. R. (1989) DNA divergence among hominoids. Evolution 43, 925–942. Fig. 1. [A] Assignment of cri du chat syndrome genomic unique Fibison, W. J., Budarf, M., McDermid, H., Greenberg, F., and DNA sequence in human (HSA5), chimpanzee (PTR 4), gorilla (GGO Emanuel, B. S. (1990) Molecular studies of DiGeorge syndrome. 19), and orangutan (PPY 4) chromosomes by By FISH technique. Am. J. Hum. Genet. 46, 888–895. In gorilla, the probe did not hybridize to chromosome 4 but the Ibraimov, A. I. (1993) The origin of modern humans: A cytogenetic hybridization signal was observed on chromsome 19 (GGO 19). [B] model. Hum. Evol. 8, 81–91. 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[B] Dia- somal pictorial legacy. Scince 215, 1525–1530. grammatic representation of chromosome bands in human chro- mosome 22 and apes’ equivalent chromsomes 23 (ISCN, 1985)..