The shredded leaf mutation, shr1, maps near the centromere on chromosome 5 --Fox, TW, Trimnell, MR, Albertsen, MC An F2 line segregating for the shredded leaf phenotype (shr1) was grown for the purpose of mapping the mutation (Trimnell, MR et al. 2000. MNL 74:36). DNA was extracted from 20 wild-type and 24 mutant plants. These samples were subjected to SSR analysis using approximately 96 markers dispersed throughout the genome (Register, JC et al. 2001. MNL 75). From this initial screen, three markers on chromosome 5 showed some linkage with the mutation. Other SSR markers on chromosome 5 were selected for additional mapping. An estimate of linkage was based on a percent recombination value, calculated by dividing the number of wild-type class alleles by the total number of alleles represented in the mutant plant samples. Failed PCR reactions were not included in the total allele calculation. As shown in the table below, five markers on chromosome 5 showed linkage with the mutation., with the two markers in bin 5.04 (phi330507 and phi386223) mapping nearest to the trait. Markers distal to bin 5.04 were not as tightly linked to shr1. No linkage was found for markers on the short arm of chromosome 5, suggesting that shr1 maps near the centromere on the long arm of chromosome 5, most likely in bin 5.04.

Allele segregations in F2 mapping population

Probe C5 bin Wild-type plants Mutant plants % Recombination
phi330507 5.04 9AC; 3C 1AC; 23A 2.1
phi386223 5.04 2A; 13AB; 5B 22A; 2AB 4.2
phi196387 5.06 13AB; 5B 19A; 5AB 10.4
phi085 5.07 4A; 14AD 8AD; 15D 17.4
bnlg118 5.07 3D; 4DE; 9E 12D; 4DE; 2E 22.2


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