Biomedical subjects

Sujit Ghosh

Publications and source records attributed to Sujit Ghosh.

3 recordsLinked to original sources

PubMed2006

Major gene detection for fusiform rust resistance using Bayesian complex segregation analysis in loblolly pine.

The presence of major genes affecting rust resistance of loblolly pine was investigated in a progeny population that was generated with a half-diallel mating of six parents. A Bayesian complex segregation analysis was used to make inference about a mixed inheritance model (MIM) that included polygenic effects and a single major gene effect. Marginalizations were achieved by using Gibbs sampler. A parent block sampling by which genotypes of a parent and its offspring were sampled jointly was implemented to improve mixing. The MIM was compared with a pure polygenic model (PM) using Bayes factor. Results showed that the MIM was a better model to explain the inheritance of rust resistance than the pure PM in the diallel population. A large major gene variance component estimate (> 50% of total variance), indicated the existence of major genes for rust resistance in the studied loblolly pine population. Based on estimations of parental genotypes, it appears that there may be two or more major genes affecting disease phenotypes in this diallel population.

Basidiomycota↗

PubMed2006

Kinetic stability plays a dominant role in the denaturant-induced unfolding of Erythrina indica lectin.

The urea-induced denaturation of dimeric Erythrina indica lectin (EIL) has been studied at pH 7.2 under equilibrium and kinetic conditions in the temperature range of 40-55 degrees C. The structure of EIL is largely unaffected in this temperature range in absence of denaturant, and also in 8 M urea after incubation for 24 h at ambient temperature. The equilibrium denaturation of EIL exhibits a monophasic unfolding transition from the native dimer to the unfolded monomer as monitored by fluorescence, far-UV CD, and size-exclusion FPLC. The thermodynamic parameters determined for the two-state unfolding equilibrium show that the free energy of unfolding (DeltaGu, aq) remains practically same between 40 and 55 degrees C, with a value of 11.8 +/- 0.6 kcal mol(-1) (monomer units). The unfolding kinetics of EIL describes a single exponential decay pattern, and the apparent rate constants determined at different temperatures indicate that the rate of the unfolding reaction increases several fold with increase in temperature. The presence of probe like external metal ions (Mn2+, Ca2+) does not influence the unfolding reaction thermodynamically or kinetically; however, the presence of EDTA affects only kinetics. The present results suggest that the ability of EIL to preserve the structural integrity against the highly denaturing conditions is linked primarily to its kinetic stability, and the synergic action of heat and denaturant is involved in the unfolding of the protein.

Calcium↗

PubMed2004

A blocking Gibbs sampling method to detect major genes with phenotypic data from a diallel mating.

Diallel mating is a frequently used design for estimating the additive and dominance genetic (polygenic) effects involved in quantitative traits observed in the half- and full-sib progenies generated in plant breeding programmes. Gibbs sampling has been used for making statistical inferences for a mixed-inheritance model (MIM) that includes both major genes and polygenes. However, using this approach it has not been possible to incorporate the genetic properties of major genes with the additive and dominance polygenic effects in a diallel mating population. A parent block Gibbs sampling method was developed in this study to make statistical inferences about the major gene and polygenic effects on quantitative traits for progenies derived from a half-diallel mating design. Using simulated data sets with different major and polygenic effects, the proposed method accurately estimated the major and polygenic effects of quantitative traits, and possible genotypes of parents and progenies. The impact of specifying different prior distributions was examined and was found to have little effect on inference on the posterior distribution. This approach was applied to an experimental data set of Loblolly pine (Pinus taeda L.) derived from a 6-parent half-diallel mating. The result indicated that there might be a recessive major gene affecting height growth in this diallel population.

Chromosome Mapping↗