1370 (a)
The rest of accessions
LEOH35b
1370
500, 370,200,180, 120
(b)
Anastasia, Royesta, Vision,
BN4, Zapotec, Bond
1300 (b)
Anastasia, Ch89, Malpica,
Royesta, Odisea, Zapotec,
LA2617, Flor de Baladre,
Much30, Teticabra, Vision,
Bond, Much128, Mor207,
EPSO42, Raf
LEOH36
1300
1120, 180 (a)
The rest of accessions
224 (a)
The rest of accessions
LEOR B
224
160, 64(b)
LA1610
The size of the fragments amplified by PCR in 4 SNPs was bigger than expected (probably
due to the presence of introns). Results indicated that electronic searching is a sound approach, but
showed the need to validate the candidate polymorphisms.
All the commercial F1 hybrids could be easily distinguished by just one SNP or a combination
of few SNPs, but the variability detected between and within traditional cultivars was extremely low.
Only the LEOH36 marker (Fig. 1) was able to distinguish between some traditional cultivars of the
Muchamiel type and other local cultivars, like Flor de Baladre and Teticabra. The higher variability
found for commercial hybrids may be due to their introgressions of resistance genes from wild
species.
Yang et al. (2003) reported that SNPs discovered in the EST database had a high probability
(53.5%) of detecting SNPs between 19 varieties. Accordingly, in the cultivated accessions that we
have analyzed, 60% of the studied SNPs detected polymorphisms, but almost all the Spanish
traditional cultivars remained undifferentiated. Therefore, in silico discovery of SNPs using non-
selected EST data is not enough efficient for this purpose. We are presently following two
approaches, electronic search of SNPs using available sequence data from genes putatively
involved in plant domestication, and sequencing SRAP bands that have shown as polymorphic
between tomato cultivars.
Figure 1. Electrophoretic patterns for 17 tomato local cultivars using SNP LEOH36.
1300 bp
1120 bp
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