O. G. Dely szerk.: Vertebrata Hungarica 21. (Budapest, 1982)
Daravskii, I. S. ; Kupriyanova, L. A.: Rare males in parthenogenetic lizard Lacerta armeniaca Méhely 69-76. o.
la humans mutations (i.e. tfm, the testicular feminization), structural abberations (the deficiency of Y chromosome) inducing the abnormal development of male genotype are known to occur (SIMPSON 1979, ROSENFELD et al. 1979). In wood lemming of the genus Myopu s the deficiency of X + chromosome has been also demonstrated: the short arm of the XT 1" chromosome of X"^ females appeared to be considerably shorter than that of the X chromosome of normal XX females (HERBST et al. 1978). Analogical abberation has also been discovered in the sex chromosome of rare males of the parthenogenetic stick insect Carausius morosu s Br. (PIJNACKER & FERWERDA 1980). Altogether, these observations suggest that some abberation and in heterogametic sex often the deficiency of sex chromosomes may lead to alternative gonad differentiation, that is, sex reversion. Cases of sex reversion in both directions induced by hormon (steroid) on the fish Oryzias latipe s shows that in this organism the sex chromosomes do not differ fundamentally from the autosomes and the chromosome mechanism of sex determination is in an early stage of evolution (MITTWOCH 1975). The same reasoning may also be applied to explain the influence of temperature of the gonad differentiation of both the male and the female sexes in amphibian larvae and embryos of turtles (PIO 1973, PIEAU 1975). The fact that in lizards sex chromosomes are found only in comparatively few species, also testifies to their recent origin. However, some facts give opportunity to suppose that, at any rate, the Y-chromosome of male Cnemidophorus tigri s (COLE 1979) and W-chromosome of female L. armeniac a are already sufficiently stabilized and play the determining role in their sex differentiation. At present many works have been devoted to the investigation of the role of H-Y antigen in gonad differentiation. But we know no works of this kind done on lizards. It has been established that H-Y antigen is detected in the gonads of individuals of the heterogametic sex. In the uncaudata amphibia with homomorphic sex chromosomes heterogamety was revealed by the presence of H-Y antigen (ZABORSKI 1979). However, recently it has been shown that H-Y antigen is also expressed in the gonads of sex-reversed male chicken embryos with homomorphic sex chromosomes, in intersex saansky goats and some human families (in man with XX chromosomes) (ENGEL & WENIGER 1979, WACHTEL 1979). The authors made an assumption that genes for H-Y antigens exist in the genome of both sexes. According to MITTWOCH's (1979) opinion, H-Y antigen is detected in individuals of that sex whose gonads grow quicker (i.e. in the testes in mammals and in the ovary in birds). FREDGA nnd his coauthors (FREDGA et al. 1980) believe that the abberation of the X +chromosome of the wood lemming of the genus Myopu s interferes with the development of H-Y antigen in XY embryos and therefore these embryos become females. Considering the observation described above, we suggest that the rare males of parthenogenetic lacertid lizards with ZW sex chromosomes, whose gonadal sex does not correspond with their chromosomal sex, could be used as a model for the investigation of H-Y antigen and of its role in the process of development and disturbance of sexual differentiation of these lizards. Rare males, as it was mentioned, occur in parthenogenetic teiid lizards of the genus Cnemidophoru s. Karyological study has shown that the males appeared to be tri- (3n C. neomexicanu s x C. inornatus ) and tetraploid (4n C . sonora e x C. tigri s ) individuals which originated from matings of di- and triploid unisexual females with males of bisexual species (LOWE et al. 1970, CUELLAR & MjcKINNEY 1976). The mitotic and meiotic activity as well as a few spermatids of unknown ploidy and no mature spermatozoa were observed in the testes of the above and other hybrid teiid males. It was just the infrequency of spermatids which prevented the authors from stating with certainty anything about their fertility. No males were discovered among teiid parthenogenetic lizards which were diploid and indistinguishable from the females, like the males of L. armeniaca . This phenomenon could possibly be explained by the fact that lacertid females are of the heterogametic (ZW) sex. It is known that the actively induced process of the development of the heterogametic sex is more complex than that of the homogametic one and it presents more opportunities for different kinds of abnormalities. Teiid males of C. tigris , unlike lacertid males, are of the heterogametic (XY) sex (COLE et al. 1969, BULL 1978, COLE 1979) and parthenogenetic teiid females are probably of the homogametic sex. The same explanation could be given to the fact that unlike lacertid lizards, where hybridization results in the appearance of hybrid but sterile females, in teiid lizards this leads to both hybrid tri- and tetraploid males (C. sonora e x C. tigris with XXXY sex chromosomes; LOWE et al. 1970) and females (C. sonora e x C. tigri s with XXXX sex chromosomes; COLE 1979). The extremely rare occurrence of males In populations of unisexual lizards of the genus
