UDC 576.316; 598.112 Original scientific paper THE DISTRIBUTION OF CONSTITUTIVE HETEROCHROMATIN AND NUCLEOLUS ORGANIZERS IN LIZARDS OF THE FAMILY LACERTIDAE (SAURIA) Mladen VUJOŠEVIĆ and Jelena BLAGOJEVIĆ Department of Genetics, Institute for Biological Research, 29 novembra 142, 11060 Belgrade, Yugoslavia Karyotypic structure of eight species from the family Lacertidae (Podarcis sicula, P. muralis, Lacerta viridis, L. trilineata, L. melisellensis, L. taurica, L. agilis and Algiroides nigropuctatus) was analyzed regarding the distribution and amount of constitutive heterochromatin, and the presence and localization of nucleolus organizers. All species have the same number and morphology of chromosomes, 36 acrocentric macrochromosomes and two microchromosomes. Interspecies variability in the number and position of nucleolus organizers was detected. Constitutive heterochromatin was present in the centromeric region in all species, while terminal localization of constitutive heterochromatin characterized four of them and interstitial only two. It was established that NORs and intercalar and terminal C-bands could be used as good landmarks for distinguishing species of lacertidae lizards. Key words: Lacertidae, karyotypes, NORs, C-bands Corresponding author: Mladen Vujošević, Department of Genetics, Institute for Biological Research, 29 novembra 142, 11060 Belgrade, Yugoslavia, e-mail: mladenvu@ibiss.bg.ac.yu