z-logo
open-access-imgOpen Access
Highly Condensed Potato Pericentromeric Heterochromatin Contains rDNA-Related Tandem Repeats
Author(s) -
Robert M. Stupar,
Junqi Song,
Ahmet L. Tek,
Zhukuan Cheng,
Feifei Dong,
Jiming Jiang
Publication year - 2002
Publication title -
genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.792
H-Index - 246
eISSN - 1943-2631
pISSN - 0016-6731
DOI - 10.1093/genetics/162.3.1435
Subject(s) - heterochromatin , biology , tandem repeat , genetics , repeated sequence , genome , direct repeat , intergenic region , dna , constitutive heterochromatin , gene , ploidy , concerted evolution , ribosomal dna , spacer dna , dna sequencing , chromosome , phylogenetics
The heterochromatin in eukaryotic genomes represents gene-poor regions and contains highly repetitive DNA sequences. The origin and evolution of DNA sequences in the heterochromatic regions are poorly understood. Here we report a unique class of pericentromeric heterochromatin consisting of DNA sequences highly homologous to the intergenic spacer (IGS) of the 18S.25S ribosomal RNA genes in potato. A 5.9-kb tandem repeat, named 2D8, was isolated from a diploid potato species Solanum bulbocastanum. Sequence analysis indicates that the 2D8 repeat is related to the IGS of potato rDNA. This repeat is associated with highly condensed pericentromeric heterochromatin at several hemizygous loci. The 2D8 repeat is highly variable in structure and copy number throughout the Solanum genus, suggesting that it is evolutionarily dynamic. Additional IGS-related repetitive DNA elements were also identified in the potato genome. The possible mechanism of the origin and evolution of the IGS-related repeats is discussed. We demonstrate that potato serves as an interesting model for studying repetitive DNA families because it is propagated vegetatively, thus minimizing the meiotic mechanisms that can remove novel DNA repeats.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here