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.

Table 1. Contents of DNA-fuxin in the nuclei of cells of males L. armeniaca. L. portschinski

i and a female L. dahl

i x L. portschinskii Average value of Coefficient Species Tissues Number of nuclei DNA-fuxin (in nominal units) X + S of variation (%) V Ploidy level L. armeniaca blood 100 106.3 ± 6.9 6.3 2n L. portschinskii it 30 108.2 ± 6.8 6.3 2n L. dahli x L. portschinskii " 50 140.0 ± 5.5 3.9 3n L. armeniaca testis (spermatids) 50 59.7 ±7.3 12.2 n L. portschinskii " 41 51.0 ± 4.0 7.6 n The pictures of spermatogenesis on paraffine sections of the gonads of both of the males practically did not differ. A usual picture was observed: spermatogonia! cells were placed at the base of the basal membrane, then followed several rows of dividing spermatocytes I and II and spermatids at different stages of development, and rather scarce spermatozoids (Plate II.: Figs 7-9). The pictures described above do not differ essentially from those which are observed in males of other lizards at this period of the year (CHRISTIAN 1971). It should be noted that unlike the male and the intersex of L. armeniac

a studied earlier, in the newly discovered male the typical order of cell row disposition was observed. Thus, females of L. armeniac

a (from 2 populations) have a diploid set of acrocentric chromosomes with probably sex (ZW) chromosomes: 2 n = 38:354A+3m. Complex studies of the male of L. armeniac

a show this male to be diploid, and by its nature, to be analogous to the other two diploid nonhybrid male individuals of L. armeniac

a and is different from the triploid hybrid male L. rostombekov

i x L. radde

i (DAREVSKY et al. 1973) and from tetraploid and also hybrid females (DAREVSKY & KULIKOVA 1964, KUPRIY

ANOVA 1973). The pictures of spermatogenesis do not differ from those in the control male. Mitotic and meiotic activities are observed in the testes which end in forming numerous spermatids and a small number of spermatozoids. Mean DNA content in the spermatids approximately fits the haploid level. It remains unknown, whether spermatogenesis is completed by the process of spermatid maturation and by the formation of fertile spermatozoids. In any case, proceeding from all what has been said above, it is only possible to assume that the diploid male of the parthenogenetic species L. armeniac

a is fertile and has originated as a result of sex reversion. Returning to the reasons of appearance of such males in natural populations, we think it is reasonable to consider some problems revelant to sex determination. Sex differentiation is known to be genetically and hormonally regulated. Classical, morphological and experimental data disclose the sexual bipotentuality of the gonads. WONDER (1980) writes "in mammals, in the absence of a testes, the female sex differentiation of the reproductive system occurs". As the male in mammals is heterogametic, the author comes to the conclusion that the determining factor of sex differences of the reproductive system is the gonad of the heterogametic sex. This assumption is supported by the fact that in birds, where the female,unlike in mammals,is the heterogametic sex, the determining factor of the differentiation is not the testes but the ovary. The gonad of the heterogametic sex, as a rule, grows quicker than and therefore suppresses the growth of the gonad of the alternative sex. In mammals the testes suppress the growth of the potential ovary tissue of the testes (the cortex), in birds on the contrary the quickly growing ovary suppresses the testicular tissue of the ovary (the medula) (WOLF 1980). More and more information is now available concerning the genetic control of sexual determination. According to MITTWOCH (1975, 1979), segments of sex chromosomes regulating the rate of growth of the bipotential gonad, induce its development into the testes or the ovary.