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Evolutionary dynamics of satellite DNA in plant genomes
ÁVILA ROBLEDILLO, Laura
Satellite DNA (satDNA) belongs to the highly repetitive fraction of eukaryotic genomes. It is best characterized by the formation of long arrays of almost identical sequences that are tandemly repeated. These repeats are widely distributed in plant species where they can make up a substantial proportion of their genomes. Despite the long history of satDNA research, the classic methodology did not allow for its comprehensive characterization. Consequently, the fragmentary information gathered during the last 60 years does not answer the many questions surrounding the evolution of these elements. The development of new techniques in sequencing, together with the availability of new bioinformatics tools for analyzing different genome fractions, has presented an opportunity to advance studies of tandem repeats. This thesis describes the landscape characterization of satDNA in the genome of Fabeae species by exploring the diversity of satDNA within a genome, the association of these elements with functional centromeres, as well as their genome-wide organization. We employed new computational pipelines specifically designed for the analysis of tandem repeats from next generation sequencing data, and combined their results with molecular and cytogenetic methods to achieve comprehensive characterization of the satellite repeats.
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Molekulární fylogeneze a genetická diverzita nejbližších příbuzných rodu Pisum
Sedláková, Veronika
The topic of this work was studied genetic diversity and phylogeny of selected wild species Lathyrus neurolobus Boiss. & Heldr., which is closely related to cultivated pea, using modern methods of molecular phylogenetics. Genotypes of L. neurolobus were obtained from Department of Botany at Palacký University in Olomouc, genomic DNA was isolated of these genotypes and samples were subjected to analysis using SSR and iPBS markers. It was found that for assessment of genetic diversity is suitable method of iPBS markers, where the average value of polymorphic information content is very high (PIC=0,928). According to evaluated markers polymorphism and assembled dendrograms was found that for search of relationship between place of origin and placement in dendrogram, will be appropriate the method of SSR markers, but only in case of selection informative markers. There was also confirmed transferability of SSR markers designed for pea to wild species of another genus.
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Molekulární fylogeneze a genetická diverzita nejbližších příbuzných rodu Pisum
Sedláková, Veronika
During the process of domestication and selection reduction of genetic diversity of cultivated crops occurred. Currently the main interest of breeders is to transfer some of crop wild relatives’ genes to cultivated crops. Those genes of interest are related e.g. with desease and pest resistance or drought resistance. Hybridization of wild and cultivated species is prevented by reproductive isolation. The frequent phonomenon in hybrids is called nuclear-cytoplasmic incompatibility, which is manifested by reduced fertility, sterility or lethality. In this phenomenon occurs conflict between nuclear-encoded genes with genes encoded in the organellar genomes. The identified accD candidate gene responsible for nuclear-cytoplasmic incompatibility in pea is highly variable due to insertions and deletions. High variability of the accD gene was also confirmed in the genera Lathyrus and Vicia. Variability was observed in gene sequence lenghts caused by presence of indels and single nucleotide polymorphisms. In comparative analysis with other regions of cpDNA commonly used in phylogenetics, the region of the accD gene had the highest value of parsimonially informative sites. The phylogeny derived from the region of the accD gene corresponds to the phylogeny based on combined chloroplast markers, therefore the accD gene may be suitable for this type of analysis.
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