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Titolo:
Recombination and spontaneous mutation at the major cluster of resistance genes in lettuce (Lactuca sativa)
Autore:
Chin, DB; Arroyo-Garcia, R; Ochoa, OE; Kesseli, RV; Lavelle, DO; Richelmore, RW;
Indirizzi:
Univ Calif Davis, Dept Vegetable Crops, Davis, CA 95616 USA Univ Calif Davis Davis CA USA 95616 Vegetable Crops, Davis, CA 95616 USA Univ Massachusetts, Dept Biol, Boston, MA 02125 USA Univ Massachusetts Boston MA USA 02125 s, Dept Biol, Boston, MA 02125 USA
Titolo Testata:
GENETICS
fascicolo: 2, volume: 157, anno: 2001,
pagine: 831 - 849
SICI:
0016-6731(200102)157:2<831:RASMAT>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
DOWNY MILDEW RESISTANCE; FLAX RUST RESISTANCE; DISEASE-RESISTANCE; NUCLEOTIDE-BINDING; BREMIA-LACTUCAE; MEIOTIC INSTABILITY; CLADOSPORIUM-FULVUM; DIVERGENT SELECTION; DEATH PROCESS; WILD LACTUCA;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
71
Recensione:
Indirizzi per estratti:
Indirizzo: Richelmore, RW Univ Calif Davis, Dept Vegetable Crops, 1 Shields Ave, Davis, CA 95616 USA Univ Calif Davis 1 Shields Ave Davis CA USA 95616 95616 USA
Citazione:
D.B. Chin et al., "Recombination and spontaneous mutation at the major cluster of resistance genes in lettuce (Lactuca sativa)", GENETICS, 157(2), 2001, pp. 831-849

Abstract

Two sets of overlapping experiments were conducted to examine recombination and spontaneous mutation events within clusters of resistance genes in lettuce. Multiple generations were screened for recombinants using PCR-based markers flanking Dm3. The Dm3 region is not highly recombinagenic, exhibiting a recombination frequency 18-fold lower than the genome average. Recombinants were identified only rarely within the cluster of Dm3 homologs and nocrossovers within genes were detected. Three populations were screened forspontaneous mutations in downy mildew resistance. Sixteen Dm mutants were identified corresponding to spontaneous mutation rates of 10(-3) to 10(-4) per generation for Dm1, Dm3, and Dm7. All mutants carried single locus, recessive mutations at the corresponding Dm locus. Eleven of the 12 Dm3 mutations were associated with large chromosome deletions. When recombination could be analyzed, deletion events were associated with exchange of flanking markers, consistent with unequal crossing over; however, although the numberof Dm3 paralogs was changed, no novel chimeric genes were detected. One mutant was the result of a gene conversion event between Dm3 and a closely related homolog, generating a novel chimeric gene. In two families, spontaneous deletions were correlated with elevated levels of recombination. Therefore, the short-term evolution of the major cluster of resistance genes in lettuce involves several genetic mechanisms including unequal crossing over and gene conversion.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 00:09:35