How do Alliaceae stabilize their chromosome ends in the absence of TTTAGGG sequences?
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TheArabidopsis-type telomeric repeats (5′-TTTAGGG-3′) are highly conserved. In most families of different plant phyla they represent the basic sequence of telomeres that stabilize and protect the chromosome termini. The results presented here show that Alliaceae and some related liliaceous species have no tandemly repeated TTTAGGG sequences. Instead, their chromosomes reveal highly repetitive satellite and/or rDNA sequences at the very ends. These apparently substitute the original plant telomeric sequences in Alliaceae. Both sequence types are very active in homologous recombination and may contribute to the stabilization of chromosome termini via compensation of replication-mediated shortening.
Key wordsAlliaceae rDNA satellite DNA telomeric sequences
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