Cytogenetic study of several species of Lacerta (Lacertidae, Reptilia) with particular reference to sex chromosomes

Abstract

The karyotypes of 4 european species of Lacertidae were determined in hepatic tissue cultures. The chromosomal formula typical of the Lacertidae (2n = 36M + 2 m) was found in L. muralis, L. sicula campestris and L. viridis; no morphologically differentiated sex chromosomes were identified in these 3 species.A population of L. vivipara caught in the Massif Central (France) shows the following diploid number: 2n~?=32A+Za Z~ W, 2nd=32A+Z~ Z~ Z2Z2. The existence of the submetacentric W in the female karyotype can be explained by centric fusion between two non homologous telocentric chromosomes. It is possible that only some populations show this rearrangement.The finding of two types of heterogamety, XY and ZW, in the same Order contributes to our knowledge of the evolution of sex chromosomes among Vertebrates.

Progressive differentiation of the W sex‐chromosome between oviparous and viviparous populations ofZootoca vivipara(Reptilia, Lacertidae)

“…5): one is present in the Spanish population and shows Chevalier et al, 1979;4, 10 and 11, Kupriyanova & Böhme, 1997;5 and 14, Odierna et al, 1993;6, Belcheva et al, 1986;7, 8, 12, 13 and 16, Kupriyanova & Rudi, 1990;9 and 15, Kupriyanova et al, 1995;17 and 18, Kupriyanova, 1990. heterochromatin on the centromeres of a few elements and an acrocentric or subtelocentric W sex-chromosome with heterochromatin only on the centromere; another type is found in populations of central western Europe and possesses conspicuous centromeric bands of heterochromatin on all of the chromosome pairs and a metacentric W chromosome with paracentromeric and telomeric heterochromatin bands; the third population, living east and possibly north of the Carpathian Mountains, has many elements with interstitial and telomeric heterochromatin and an acrocentric W chromosome with heterochromatin in telomeric and subtelomeric areas.…”

“…One type, characterized by a uniarmed W chromosome, is present in several Asiatic populations (Oguma, 1934;Kupriyanova, 1986Kupriyanova, , 1990Kupriyanova & Rudi, 1990), in most of European Russia, on the northern slops of the Carpathian Mountains (Kupriyanova & Rudi, 1990;Odierna et al, 1993;Kupriyanova et al, 1995;Kupriyanova & Böhme, 1997) and in females of the subspecies Z. v. pannonica from Austria (Kupriyanova & Böhme, 1997). The other type is characterized by a biarmed W chromosome and has been reported in several populations from central Europe (Chevalier, 1969;Chevalier et al, 1979;Odierna et al, 1993;Kupriyanova & Böhme, 1997), Bulgaria (Belcheva et ai, 1986), from the southern slope of the Carpathian mountains (Kupriyanova, 1990;Kupriyanova & Rudi, 1990), and recently also Sweden and the Baltic regions of Russia (Kupriyanova et al, 1995).…”

Natural selection and geographical variation in a known sex-linked gene of the Common Lizard in Europe. Implications for chromosomal evolution

“…The outcome was a large metacentric neo-W, one arm of which was homologous to the ancestral Z (homomorphic with the ancestral W), the other arm being homologous to the remaining autosome of the pair carrying the MPI locus. Pairs 11 and 15 of the L. vivipara karyotype were involved (Chevalier et a!., 1979), but which one bore the enzyme locus is a question whose answer will have to wait until the gene controlling mannose-phosphate-isomerase synthesis is probed.…”

“…At the karyotype level, however, there exist two very distinct kinds of populations according to the literature. From chromosomal studies, some populations from Switzerland and the Netherlands (van Brink, 1959) and Russia (Orlova and Orlov, 1969) have been assessed to be homomorphic, while others, from France's Massif Central, have been shown to have a visible Z1Z2W heteromorphic sex-determination system (Chevalier et a!., 1979).…”

Studies on the chromosomes of the rainbow lizard Agama agama agama (L.) with notes on polypoidy in the spermatocytes.

“…Chromosomal sex differentiation is not always obvious, even in species where the male animal is normally morphologically distinguishable from the female. However, cases of both male and female heterogamety have been reported (Chevalier et al 1979, Becak and Becak 1969, Bull 1978.…”