PhD. Topics

Analysis of repetitive sequences in the genome of fish parasites and their role in chromosome evolution

Zoology, daily form

2025

RNDr. Martina Orosová, PhD.

Contact:

Comenius University Bratislava

Most eukaryotic genomes contain a high level of repetitive sequences, collectively referred to as the repeatome, which constitute a significant part of nuclear DNA. They can occupy from 10 to 80% of a genome. These sequences can be organized in tandem arrays and located at small number of loci on chromosomes as satellite DNA, or dispersed throughout the genome as so-called transposable elements. Repetitive sequences play important roles in gene expression, chromosome segregation, nuclear organization, and are especially important in species evolution and adaptation. They also serve as valuable tools for studying evolution and phylogeny. The topic of repetitive sequences in fish parasites is a completely new field. Currently, only preliminary data are available regarding the types of repeat families and their genomic proportions in three species. This dissertation will focus on a detailed study of the chromosomes of fish parasites. The aim is the de novo identification and characterization of repetitive sequences and the development of species-specific chromosomal markers. A selection of bioinformatic methods designed for analyzing repetitive DNA elements from low-coverage whole-genome sequencing data will be applied. Fluorescence in situ hybridization (FISH) will then be used to map these repeats on chromosomes, allowing the study of their genomic distribution in model parasite species. We expect that comparing individual repeats and their chromosomal locations between closely and distantly related species will provide novel insights into their evolution and amplification in the genomes of fish parasites. In addition to laboratory work, the research will include fieldwork focused on collecting model parasite species from fish in various aquatic ecosystems in Slovakia as well as abroad.