The centromeric regions of potato chromosomes contain megabase-sized tandem arrays of telomere-similar sequence.
Telomere-similar sequences have been found in non-telomeric regions in various eukaryotic species. Centromeric regions often harbor such interstitial telomeric repeats (ITRs). We isolated a 2.8 kb ITR, pSbTC1, in a diploid potato species Solanum bulbocastanum. DNA sequences related to the pSbTC1 family are widely distributed in different Solanum species. The pSbTC1-related sequences are organized into tandem arrays and located mainly in the centromeric regions of potato chromosomes. Most notably, the pSbTC1-related sequences have undergone extensive amplification and a single array can span up to multiple megabases. These results suggest that the pSbTC1-related sequences are not simple relics of ancient events in karyotype evolution, such as chromosomal fusions. We also demonstrated that the pSbTC1-related sequences are heavily methylated and are associated with highly condensed centromeric heterochromatin.
Tek
Ahmet L
AL
Department of Horticulture, University of Wisconsin-Madison, Madison, WI 53706, USA.
Jiang
Jiming
J
D001483:Base Sequence; D002503:Centromere / Q000235:genetics*; D019175:DNA Methylation; D018744:DNA, Plant / Q000235:genetics*; D006570:Heterochromatin / Q000235:genetics*; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid; D032322:Solanum / Q000235:genetics*; D016615:Telomere / Q000235:genetics*
D018744:DNA, Plant; D006570:Heterochromatin