Sex chromosome evolution in selected taxa of teleost fishes (Teleostei)
- Resource Type
- Authors
- Pavlica, Tomáš
- Source
- Subject
- CGH
sex chromosomes
chromozómové přestavby
širokohlavci
kryptické druhy
killifish
pohlavní chromozómy
banjo catfish
karyotype variability
karyotypová variabilita
cryptic species
WCP
halančíci
repetitive DNA
synaptonemal complexes
synaptonemální komplexy
repetitivní DNA
karyotype rearrangements
- Language
- Czech
Teleosts represent more than half of the extant vertebrate species. They show a wide range of mechanisms driving both sex determination and sex differentiation, including nine sex chromosome systems described to date. Teleost sex chromosomes are generally considered as evolutionarily young, therefore they are suitable for an analysis of the early stages of evolution of these unique genomic regions. The aim of the current thesis was to analyze the presence and degree of differentiation of sex chromosomes in two Nothobranchius killifish species and one Bunocephalus banjo catfish representative using conventional and molecular cytogenetic methods. Different populations of N. kadleci and N. furzeri analysed in this thesis shared anXY sex chromosome system. Despite the obvious heteromorphy of their sex chromosomes, comparative genome hybridization (CGH) did not show any region of differentiation. Analysis of synaptonemal complexes by immunostaining coupled with the mapping of 18S rDNA and telomeric repeats using fluorescent in situ hybridization (FISH) showed mainly standard pairing with the contribution of synaptic adjustment. Pachytene spreads of females from one N. furzeri population contained a small supernumerary chromosome which was not present in metaphases of studied somatic cells. Distribution...