Gb. Poulsen et al., DIFFERENTIAL ABUNDANCE OF SIMPLE REPETITIVE SEQUENCES IN SPECIES OF BRASSICA AND RELATED BRASSICACEAE, Plant systematics and evolution, 190(1-2), 1994, pp. 21-30
Six Brassica species, known as the ''triangle of U'', and four species
from related genera were characterized by DNA fingerprinting with sim
ple repetitive oligonucleotide probes. Our results show that CT-, TCC-
, and GTG-repeat motifs are equally abundant in the genomes of the six
Brassica species. In contrast, GATA-, GGAT-, and GACA-multimers are u
nevenly distributed among different species. As judged from the number
and strength of hybridization signals, the highest copy number of all
three motifs occurs in Brassica nigra, while the lowest is observed i
n B. oleracea. The abundance of GATA- and GACA-repeats varies in a coo
rdinate way. The amphidiploid genomes of B. juncea, B. carinata, and B
. napus each harbour intermediate amounts of (GATA)4 and (GACA)4-detec
ted repeats as compared to their diploid progenitors, thus supporting
the concept of the ''U triangle''. GATA-, GACA-, and GGAT-repeats were
also abundant in Eruca sativa and Sinapis arvensis, but not in Raphan
us sativus and Sinapis alba. These results support the idea that Brass
ica nigra is more closely related to Sinapis arvensis than to other Br
assica species such as B. rapa and B. oleracea.