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W chromosomes in Lepidoptera: evolution, diversity and molecular features
HEJNÍČKOVÁ, Martina
Sex chromosome evolution is a fascinating and very dynamic process, which is best to be studied on diverse groups of organisms. Moths and butterflies (Lepidoptera) are known for their species diversity and female heterogamety, which makes them an ideal research model. Most species of Lepidoptera have a WZ/ZZ (female/male) system, although some species lack the W chromosome. The first part of this thesis discusses possible mechanisms and points of its origin in terms of phylogeny. Specifically, it focuses on the lack of W chromosome in the group of bagworms (Psychidae), supporting recent theory about the independent origin of W chromosomes in Lepidoptera. The second part of the thesis provides valuable information about the W chromosome variability and molecular content within the group of loopers (Geometridae). Finally, the third part describes the accumulation of retrotransposons on the W chromosome in Peribatodes rhomboidaria and emphasizes their importance in the process of sex chromosome differentiation.
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Vývoj molekulárních markerů pro chromozom W u modráska \kur{Polyommatus icarus}
HRUBÁ, Monika
Tato diplomová práce se zabývá vývojem molekulárních markerů pro chromozom W u modráska Polyommatus icarus, u kterého byly nalezeny karyotypové rasy lišící se konstitucí neo-pohlavních chromozomů. Vyvinuté markery byly použity pro určení pohlaví pomocí PCR u čerstvě vylíhlých housenek, ze kterých byla izolována celková RNA, která bude dále použita pro testování role pohlavně antagonistické selekce ve fixaci neo-pohlavních chromozomů.
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Analýza karyotypu vakonošů (Psychidae, Lepidoptera) metodami klasické a molekulární cytogenetiky
HEJNÍČKOVÁ, Martina
Vzhledem ke svojí fylogenetické pozici hrají vakonoši (Psychidae) důležitou roli ve výzkumu původu chromosomu W u motýlů (Lepidoptera). Několik druhů vakonošů bylo testováno na přítomnost sex-chromatinu a vyšetřeno komparativní genomovou hybridizací. Navíc byl u samic pozorován lichý počet chromosomů a Z univalent. Tato práce přináší celistvý důkaz o absenci chromosomu W u vakonošů, čímž přispívá ke komplexním znalostem o evoluci chromosomu W. U vybraných druhů byl navíc analyzován karyotyp za použití rDNA a histon H3 sond. Výsledky naznačují relativní stabilitu karyotypu.
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Využití BAC klonů při studiu pohlavního chromosomu W obaleče jablečného \kur{Cydia pomonella} (Lepidoptera: Tortricidae)
DALÍKOVÁ, Martina
In the present study, the W sex-chromosome of the codling moth was studied by means of fluorescence in situ hybridization (FISH) with probes prepared from bacterial artificial chromosome (BAC), which were isolated from the codling moth BAC library. The BAC library was screened for clones derived from both the W and Z sex chromosomes using three sets of molecular markers of codling moth sex chromosomes. A total of 54 BAC clones have been obtained. In this work, only 3 W-derived BAC clones and 1 Z-derived BAC clone were further characterized by BAC-FISH mapping on chromosome preparations of pachytene oocytes; the other BAC clones have been retained for next studies. Whereas the Z-BAC probe provided a discrete hybridization signal on the Z chromosome, and surprisingly on the W chromosome, the W-BAC probes showed multiple hybridization signals distributed on the whole W chromosome, suggesting that they are mainly composed of repetitive sequences, which occur in multiple clusters on the W chromosome. The specific pattern of W-BAC hybridization signals along with the discrete signal of the Z-BAC enabled us to discriminate left/right orientation of both the W and Z chromosomes and examine specificity of W-Z pairing during meiotic prophase I.
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