Abstract
Iguanas (Squamata: Pleurodonta) form one of the most diverse groups of squamate reptiles. The group includes almost all imaginable ecomorphs - species from deserts as well from rainforests, from high mountains or living on the seashore, climbing on rocks, trees or even diving in the sea.
The genus Anolis with over 400 species is well-known as a model of adaptive radiation on Caribbean islands. One of the species of this genus, Anolis carolinensis, is also the first squamate reptile with a fully sequenced and well-annotated genome.
Despite all these facts, the iguanas are still quite poorly studied cytogenetically. From the 60ˈs and 70ˈs there have been studies reporting karyotype formulas for many species; however up to now, the more detailed knowledge about genome organization and sex determination was scarce as in other groups of reptiles due to the lack of advanced molecular-cytogenetic, genetic and genomic methods.
In our contribution we report current findings about karyotype evolution. We present the reconstruction of the ancestral karyotype and evaluate the rate of chromosomal rearrangements among iguana families.
Also, we describe sex chromosomes and although they differ between lineages, we prove they have a common origin in the whole group. We also review evidence on (non)homology of iguana sex chromosomes with those of other amniotes.
Altogether, we offer an overview of investigations about iguana cytogenetics highlighting their synapomorphies and contrastingly, the plesiomorphic characters they share with other reptiles to enlarge our knowledge and understanding of evolutionary biology, in particular the evolution of sex determination and genome organization.