Data for chromosomal localization of the
Arabidopsis-type of telomeric sequence repeats (TTTAGGG)
n are compiled for 44 species belonging to 14 families of angiosperms, gymnosperms and bryophytes. For 23 species and seven families this is the first report. Species of all families, except the
Alliaceae, revealed these sequences at their chromosome termini. This indicates that
Arabidopsis-type telomeric repeats are highly conserved. It is inferred that they represent the basic telomere sequence of higher plant phyla. In the
Alliaceae, a deviating sequence (and mechanism?) for the stabilization of chromosome termini has possibly evolved secondarily. Nine species revealed interstitial telomeric sequences in addition to the terminal ones, in three species (
Vicia faba, Pinus elliottii, P. sylvestris) also at centromeric positions. Interstitial telomeric sequences may indicate karyotype reconstructions, in particular alterations of chromosome numbers by chromosome fusion — or inversions with one breakpoint within the terminal array of repeats. They may contribute to stabilization of chromosome breaks, especially centric fissions, and increase the frequency of meiotic and illegitimate recombination.
Key words Angiosperms - gymnosperms - bryophytes - Telomeres - fluorescent in situ hybridization - karyotype evolution
Dedicated to Prof. DrRigomar Rieger at the occasion of his 65th birthday.