RECIPROCAL CHROMOSOME PAINTING BETWEEN HUMAN AND PROSIMIANS (EULEMUR MACACO MACACO AND E-FULVUS MAYOTTENSIS)

We used fluorescence in situ hybridisation to delineate the homology b etween the human karyotype and those of two lemur species (Eulemur mac aco macaco and E. fulvus mayottensis). Human and lemur chromosome-spec ific probes were established by bivariate fluorescence-activated Row s orting (FAGS) and subsequent degenerate oligonucleotide-primed CR (DOP -PCR). Reciprocal painting of human probes to lemur chromosomes and vi ce versa allowed a detailed analysis of the interchromosomal rearrange ments that had occurred during the evolution of these species. The res ults indicate that the genomes of both species have undergone only a f ew translocations during more that 45 million years of lemur and human evolution. The synteny of homologs 10 human chromosomes 3, 9, 11, 13, 14, 17, 18, 20, 21; X, and Y was found to be conserved in rile two le mur species. Taking nonprimate mammals as the outgroup for primates, a ncestral conditions for various primate chromosomes were identified an d distinguished from derived forms. Lemur chromosome painting probes w ere also used for cross-species hybridization between the two lemur sp ecies. The results support an earlier assumption, made on-the basis of chromosome banding, that the karyotypes of the two species have evolv ed exclusively by Robertsonian transformations. All probes derived fro m E. f. mayottensis chromosomes specific for homologs involved in rear rangements in E. In, macaco exclusively painted entire chromosome arms , The results further indicate that E. f. mayottensis most probably ha s a more ancestral karyotype than E. m. macaco. Probes derived from pr osimians will be useful in comparing the karyotypes of other lower pri mates, which will improve our understanding of early primate genome ev olution.