SOMATIC CONVERSION (PARAMUTATION) AT THE SULFUREA LOCUS OF LYCOPERSICON ESCULENTUM MILL. III. STUDIES WITH TRISOMICS

Publisher Website
Google Scholar
Abstract
Genetic studies carried out since 1958, have revealed at the sulfurea (sulf) locus of Lycopersicon esculentum the occurrence of a particular type of genetic instability: somatic conversion (paramutation). In vegetative cells of sulf+sulf heterozygotes the wild type allele sulf+ is heritably altered under the influence of the mutant sulf allele which is present in the same nucleus.By crossing sulf homozygotes and seven primary trisomics of the tomato (triplo-2, -5, -7, -8, -9, -10, -12) as well as a tertiary trisomic it was proven that the sulf locus is on chromosome 2, the nucleolus chromosome of the tomato.The effects of dosage are shown by the two different heterozygous trisomics which differ with regard to somatic conversion. In sulf+sulf sulf plants somatic conversion takes place very frequently; 60% of the plants (35) are variegated; that is, two conversion-active sulf alleles are very frequently able to convert one sensitive sulf+ allele. However, in sulf+sulf+sulf plants conversion has so far not been found; all plants (52) are entirely green; that is, one conversion-active sulf allele acting against two conversion-sensitive sulf+ alleles is not able to induce somatic conversion.

This publication has 0 references indexed in Scilit: