Quantitative trait locus mapping associated with earliness and fruit weight in tomato

ABSTRACT The flowering time is regarded as an important factor that affects yield in various crops. In order to understand how the molecular basis controlling main components of earliness in tomato (Solanum lycopersicum L.), and to deduce whether the correlation between fruit weight, days to flowering and seed weight, is caused by pleiotropic effects or genetic linkage, a QTLs analysis was carried out using an F2 interspecific population derived from the cross of S. lycopersicum and S. pimpinellifolium. The analysis revealed that most of the components related to earliness were independent due to the absence of phenotypic correlation and lack of co-localization of their QTLs. QTLs affecting the flowering time showed considerable variation over time in values of explained phenotypic variation and average effects, which suggested dominance becomes more evident over time. The path analysis showed that traits such as days to flowering, seed weight, and length of the first leaf had a significant effect on the expression of fruit weight, confirming that their correlations were due to linkage. This result was also confirmed in two genomic regions located on chromosomes 1 and 4, where despite showing high co-localization of QTLs associated to days to flowering, seed weight and fruit weight, the presence and absence of epistasis in dfft1.1 × dftt4.1 and fw1.1 × fw4.1, suggested that the linkage was the main cause of the co-localization

A simple computer program for quantitation and scatchard analysis of steroid receptor proteins

This paper presents a relatively simple program for the analysis of data in tissue receptor protein assays. Information is presented to the computer as c.p.m. obtained from liquid scintillation systems. The program is adaptable to clinical studies while retaining sufficient flexibility to deal with cross-competition data and the generation of regression lines for Scatchard plot analyses

Retinoids and cultured human fibroblasts: Effects on cell growth and presence of cellular retinoic acid-binding protein

We have examined the effects of retinoids on growth of cultured human skin fibroblasts from four individuals. Retinoic acid and retinol both produce a dose-dependent inhibition of growth in the four strains examined; retinoic acid was more potent than retinol in this respect. The growth inhibitory effect of retinoic acid is characterized by a decrease in the exponential growth rate, which is reversible upon removal of retinoic acid from the growth medium; the final saturation density, however, is not modified by retinoic acid treatment. No alterations of cell morphology, viability, or adhesiveness to substratum are induced by the retinoid concentrations utilized. The inhibitory effect of 10 −6 M retinoic acid on cell growth is not affected by the concentration of fetal calf serum (FCS) in the medium. In all four human fibroblast strains examined, specific binding of [ 3H]retinoic acid to cytosol is present as determined by sucrose-density gradient centrifugation. Despite the effects of retinol on fibroblast growth, no cytoplasmic binding of [ 3H]retinol could be demonstrated in these cells