CHARACTERIZATION OF SOMATIC HYBRIDS BETWEEN BRASSICA-NAPUS AND ERUCA-SATIVA USING SPECIES-SPECIFIC REPETITIVE SEQUENCES AND GENOMIC IN-SITUHYBRIDIZATION
J. Fahleson et al., CHARACTERIZATION OF SOMATIC HYBRIDS BETWEEN BRASSICA-NAPUS AND ERUCA-SATIVA USING SPECIES-SPECIFIC REPETITIVE SEQUENCES AND GENOMIC IN-SITUHYBRIDIZATION, PLANT SCI, 123(1-2), 1997, pp. 133-142
To analyze inheritance and presence of donor DNA from Eruca sativa in
progenies derived from somatic hybrids between Eruca sativa x Brassica
napus, two E. sativa specific repetitive DNA sequences were isolated
and characterized by DNA sequencing. One of the sequences, ESR64, show
ed 100% similarity with a part of the E. sativa rDNA intergenic spacer
. In situ hybridization to metaphase chromosomes of E. sativa revealed
six sites of hybridization, indicating that E. sativa has three rDNA
loci. The other clone, ESR92, was shown to be a tandemly repeated elem
ent located close to the telomeres on at least ten chromosomes. Analys
is of progenies derived from the somatic hybrids, using these two repe
titive sequences as probes, revealed the presence of E. sativa DNA. Fu
rthermore, cytogenetic analyses with genomic in situ hybridization (GI
SH), was performed, using differently labelled total DNA from the two
parental species, in combination with a preannealing step to remove co
mmon sequences. These experiments showed that labelling in B. napus wa
s restricted to the centromeric regions while a uniform distribution o
ver the chromosomes was found in E. sativa. With the GISH technique it
was also revealed that the somatic hybrid, progeny contained one or t
wo complete E. sativa chromosomes, but no intergenomic translocations
could be detected. (C) 1997 Elsevier Science Ireland Ltd.