A study of the Chromosomes of Some Lizards, with Special Remarks on the m-chromosomes

Abstract

The comparative study of chromosomes in male germ cells of some species of lizards belonging to the Lacertidae were undertaken with the purpose to find, if any, the cytotaxonomic characteristics. Takydromus tachydromoides, and T. smaragdinus show 38 chromosomes in diploid, both having a pair of the m-chromosomes of minute size, while Lacerta vivipara possesses 36 diploid chromosomes containing no m-chromosomes. The m-chromosomes exhibit a size variation by species, or even by individuals: They are exceptionally in size in a specimen of T. smaragdinus, medium sized in the ordinary specimens of the same species, and extremely small in T. tachydromoides. In L. vivipara there are no m-chromosomes. By the evidence of a gradual diminution of the m-chromosomes by species and the assumption of their final disappearance, the numerical relation of chromosomes existing in Takydromus and L. vivipara may be explicable. The correlation between the chromosome diminution and the geographical distribution of animals was considered. © 1953, Japan Mendel Society, International Society of Cytology. All rights reserved.