Extremizace složení genomu orchidejí – příčiny a souvislosti

Agency
Project number
LUAUS25297
Principle investigator
Co-principle investigator
Orchids stand out from this range, where a much higher variability was detected, ranging from 22.5–50.5%, even if they have only monocentric chromosomes. Such variability is remarkable and is probably related to the phenomenon of partial endoreplication (PE), a unique feature of orchids. This
process allows orchids to multiply only certain parts of the genome during endoreplication. This has major connotations within the genome. Species with PE have on average larger genome sizes than species with conventional endoreplication (CE), due to the accumulation of repetitive elements in
non-replicated parts of the genome. It is possible that selective accumulation or suppression of  certain repetitive elements in orchid genomes leads to the enormous variation in their nucleotide composition.
The aim of the project is to unravel the mechanism of extremes in the genome composition of orchids with PE. To this end, three basic assumptions will be tested: the source of variability is (1) in particular, third positions in codons; (2) differences in GC composition of exons and introns; (3) accumulation or loss of specific repetitive elements.