Plant & Animal Genome VI Conference Plant & Animal Genome VI Conference
S9
Department of Horticulture, University of Wisconsin-Madison, Madison, WI 53706, USA
Bacterial artificial chromosome (BAC) clones derived from sorghum and
rice centromeres were isolated using probe pSau3A9 that is conserved in
the centromeres of grass species. About 10 distinct DNA elements were
subcloned from both sorghum and rice centromeric BAC clones. All the
DNA elements cloned were repetitive and specific to centromeric
regions. The copy numbers of these repeats ranged from several hundred
up to 100,000 copies. DNA elements specific to one or few centromeres
were not found. Highly-repetitive tandem repeats were found in both
sorghum (Sau3A10 family) and rice (RSau3A4 family) centromeres. The
organization of the these two tandem repeats shared many similarities
to the pAL1 repeat located in the centromeric regions of
Arabidopsis thaliana chromosomes. While the Sau3A9 family
from sorghum is conserved in all the Gramineae species analyzed, the
other centromeric DNA families were only found in closely related
species or in some of the grass species.