Amniotes possess variability in sex determination, from environmental sex determination (ESD), where no sex chromosomes are present, to genotypic sex determination (GSD) with highly differentiated sex chromosomes. Some evolutionary scenarios postulate high stability of differentiated sex chromosomes and rare transitions from GSD to ESD. However, sex chromosome turnovers and two independent transitions from highly differentiated ZZ/ZW sex chromosomes to ESD were previously reported in the lacertid lizards. Here, we examined the homology of sex chromosomes in the wide phylogenetic spectrum of lacertids and their outgroups by comparing gene copy numbers between sexes in genes previously found to be Z-specific in some lacertids. Our current sampling covers 45 species from 26 genera including lineages supposed to possess a derived sex determining systems. We found that all tested lacertids share homologous differentiated ZZ/ZW sex chromosomes, which were present already in their common ancestor living around 85 million years ago. These differentiated sex chromosomes are not present in amphisbaenians and teiid lizards, the close relatives of lacertids. Our study demonstrates how inaccuracies in data can influence the outcome of phylogenetic reconstructions of evolution of sex determination, in this case they overestimated the number of shifts from GSD to ESD and the rate in turnovers of sex chromosomes.

• MeSH
• Cytogenetics statistics & numerical data   MeSH
• Phylogeny MeSH
• Genotype * MeSH
• Gene Dosage MeSH
• Lizards physiology   MeSH
• Evolution, Molecular MeSH
• Sex Chromosomes genetics   MeSH
• Sex Determination Processes physiology   MeSH
• Sequence Homology, Nucleic Acid MeSH
• Data Accuracy MeSH
• Environmental Exposure * MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

• MeSH
• Chromosome Aberrations diagnosis   epidemiology   MeSH
• Cytogenetics methods   statistics & numerical data   MeSH
• Abortion, Induced diagnosis   epidemiology   genetics   MeSH
• Cells, Cultured MeSH
• Humans MeSH
• Fetus cytology   MeSH
• Pregnancy Trimester, First MeSH
• Abortion, Spontaneous MeSH
• Pregnancy MeSH
• Check Tag
• Humans MeSH
• Pregnancy MeSH
• Female MeSH