Abstract
Repetitive DNA sequences have been demonstrated to play an
important role for centromere function of eukaryotic chromosomes,
including those from fission yeast,
Drosophila
melanogaster,
and humans. Here we report on the isolation of a
repetitive DNA element located in the centromeric regions of cereal
chromosomes. A 745-bp repetitive DNA clone, pSau3A9, was isolated from
sorghum (
Sorghum bicolor
). This DNA element is located
in the centromeric regions of all sorghum chromosomes, as demonstrated
by fluorescence
in situ
hybridization. Repetitive DNA
sequences homologous to pSau3A9 also are present in the centromeric
regions of chromosomes from other cereal species, including rice,
maize, wheat, barley, rye, and oats. Probe pSau3A9 also hybridized to
the centromeric region of B chromosomes from rye and maize. The
repetitive nature and its conservation in distantly related plant
species indicate that the pSau3A9 family may be associated with
centromere function of cereal chromosomes. The absence of DNA sequences
homologous to pSau3A9 in dicot species suggests a faster divergence of
centromere-related sequences compared with the telomere-related
sequences in plants.