A Fish of Multiple Faces, which Show us Enigmatic and Incredible Phenomena in Nature: Biology and Cytogenetics of the Genus Carassius

Abstract

Sexual vs asexual reproduction—unisexual vs bisexual populations—diploid vs polyploid biotypes—genetic vs environmental sex determination: all these natural phenomena are associated with the genus of teleost fish, Carassius. Two Carassius entities with completely different biological characteristics exist: one globally widespread and invasive Carassius gibelio, and the other C. carassius with decreasing trend of natural occurrence. Comprehensive biological and cytogenetic knowledge of both entities, including the physical interactions between them, can help to balance advantages of highly invasive and disadvantages of threatened species. For example, benefits of a wide-ranged colonization can lead toward extinction of native species or be compensated by parasitic enemies and lead to equilibrium. This review emphasizes the comprehensive biology and cytogenetic knowledge and importance of the Carassius genus as one of the most useful experimental vertebrate models for evolutionary biology and genetics. Secondly, the review points out that effective molecular cytogenetics should be used for identification of various species, ploidy levels, and hybrids. The proposed investigation of these hallmark characteristics in Carassius may be applied in conservation efforts to sustain threatened populations in their native ranges. Also, the review focuses on consequences of co-occurrence of native and non-native species and outlines future perspectives of Carassius research.

Divergent subgenome evolution in the allotetraploid frog Xenopus calcaratus

“…The number and position of NORs has been been extensively explored in both diploid and polyploid animals Amphibians and fish are good groups with which to explore the effect of whole genome duplication on the evolution of NOR and other ribosomal structures (Knytl, Kalous, Rylková, Choleva, Merilä and Ráb, 2018a) because both include a diversity of diploid and polyploid species (Evans et al, 2015;Knytl, Forsythe and Kalous, 2022). In most diploid and polyploid amphibians, only one chromosome pair bears a NOR (Schmid et al, 1987;Alves, de Borba, Pozzobon, Oliveira, Nirchio, Granado and Foresti, 2012;Schmid, 1982).…”

Consequences of polyploidy and divergence as revealed by cytogenetic mapping of repetitive elements in African clawed frogs (Xenopus, Pipidae)

“…However, repetitive DNA can be precisely mapped by uorescent in situ hybridization (FISH) techniques. Cytogenetic mapping of repetitive sequences has been studied in vertebrates in teleost shes [Bishani et al, 2021;Knytl et al, 2022], reptiles [Oliveira et al, 2021;Altmanová et al, 2022], birds [De Oliveira Furo et al, 2017;Kretschmer et al, 2021], and mammals [Milioto et al, 2019;Gerbault-Seureau et al, 2018].…”