Chromosome Polymorphism, Geographical Variation and Karyotypes in Sauria

Abstract

A comparative cytogenetic study was done on ten lacertilian species belonging to six families: Iguanidae, Teiidae, Amphisbaenidae, Gekkonidae, Anguidae and Scincidae. Intra-individual and intrapopulational karyotype variations apparently stemming from differences in the number of chromosomes were observed in the iguanid Tropidurus torquatus from Minas Gerais and Maranhão. A heteromorphic autosomal pair was found in another population (São Paulo) of the same species. The geographical variation may be related to the process of speciation. Intra-individual differences in the number of macro — and microchromosomes were found in a population of Amphisbaena dubia. For every new acrocentric macrochromosome, a decrease of two microchromosomes was observed. The chromosomal variation may be due to a fusion/fission process or to somatic segregation involving macro — and microchromosomes.