Microspore embryogenesis in barley: anther pre-treatment stimulates plant defence gene expression

Microspore embryogenesis (ME) is a process in which the gametophytic pollen programme of the microspore is reorientated towards a new embryo sporophytic programme. This process requires a stress treatment, usually performed in the anther or isolated microspores for several days. Despite the universal use of stress to induce ME, very few studies have addressed the physiological processes that occur in the anther during this step. To further understand the processes triggered by stress treatment, we followed the response of anthers by measuring the expression of stress-related genes in two barley (Hordeum vulgare L.) cultivars differing in their ME response. Genes encoding enzymes involved in oxidative stress (glutathione-S-transferase, GST; oxalate oxidase, OxO), in the synthesis of jasmonic acid (13-lipoxygenase, Lox; allene oxide cyclase, AOC; allene oxide synthase, AOS) and in the phenylpropanoid pathway (phenylalanine ammonia lyase, PAL), as well as those encoding PR proteins (Barwin, chitinase 2b, Chit 2b; glucanase, Gluc; basic pathogenesis-related protein 1, PR1; pathogenesis-related protein 10, PR10) were up-regulated in whole anthers upon stress treatment, indicating that anther perceives stress and reacts by triggering general plant defence mechanisms. In particular, both OxO and Chit 2b genes are good markers of anther reactivity owing to their high level of induction during the stress treatment. The effect of copper sulphate appeared to limit the expression of defence-related genes, which may be correlated with its positive effect on the yield of microspor

Taxonomy, Physiology, and Natural Products of Actinobacteria

Microbial Biotechnolog

The use of measured genotype information in the analysis of quantitative phenotypes in man

Improved laboratory methods allow one to investigate the contribution of measured allelic variability at a locus physiologically involved in determining the expression of a quantitative trait. We present statistical methods that incorporate measured genotype information into the analysis of a quantitative phenotype that allows one simultaneously to detect and estimate the effects of a measured single locus and residual polygenic effects. Likelihoods are presented for the joint distribution of the quantitative phenotype and a measured genotype that are appropriate when the data are collected as a sample of unrelated individuals or as a sample of nuclear families. Application of this method to the analysis of serum cholesterol levels and the concentration of the group specific component (Gc) are presented. The analysis of the contribution of the common Gc polymorphism to the determination of quantitative variability in Gc using smaples of related and unrelated individuals presents, for the first time, the simultaneous estimation of the frequencies and the effects of the genotypes at a measured locus, and the contribution of residual unmeasured polygenes to phenotypic variability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65935/1/j.1469-1809.1986.tb01037.x.pd

Analysis of genetic and environmental sources of variation in serum cholesterol in Tecumseh, Michigan. V. Variance components estimated from pedigrees

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65164/1/j.1469-1809.1979.tb00668.x.pd

Detecting Linkage between a Trait and a Marker in a Random Mating Population without Pedigree Record

Modern linkage-based approaches employing extended pedigrees are becoming powerful tools for localizing complex quantitative trait loci. For these linkage mapping methods, it is necessary to reconstruct extended pedigrees which include living individuals, using extensive pedigree records. Unfortunately, such records are not always easy to obtain and application of the linkage-based approaches has been restricted. Within a finite population under random mating, latent inbreeding rather than non-random inbreeding by consanguineous marriages is expected to occur and is attributable to coalescence in a finite population. Interestingly, it has been revealed that significant random inbreeding exists even in general human populations. Random inbreeding should be used to detect the hidden coancestry between individuals for a particular chromosomal position and it could also have application in linkage mapping methods. Here we present a novel method, named finite population based linkage mapping (FPL) method, to detect linkage between a quantitative trait and a marker via random inbreeding in a finite population without pedigree records. We show how to estimate coancestry for a chromosomal position between individuals by using multipoint Bayesian estimation. Subsequently, we describe the FPL method for detecting linkage via interval mapping method using a nonparametric test. We show that the FPL method does work via simulated data. For a random sample from a finite population, the FPL method is more powerful than a standard pedigree-based linkage mapping method with using genotypes of all parents of the sample. In addition, the FPL method was demonstrated by actual microsatellite genotype data of 750 Japanese individuals that are unrelated according to pedigree records to map a known Psoriasis susceptible locus. For samples without pedigree records, it was suggested that the FPL method require limited number of individuals, therefore would be better than other methods using thousands of individuals

Homozygosity by descent mapping of blood pressure in the Old Order Amish: evidence for sex specific genetic architecture

<p>Abstract</p> <p>Background</p> <p>High blood pressure is a well established risk factor for morbidity and mortality acting through heart disease, stroke and cardiovascular disease. Genome wide scans have linked regions of nearly every human chromosome to blood pressure related traits. We have capitalized on beneficial qualities of the Old Order Amish of Lancaster, PA, a closed founder population with a relatively small number of founders, to perform a genome wide homozygosity by descent mapping scan. Each individual in the study has a non zero probability of consanguinity. Systolic and diastolic blood pressures are shown to have appreciable dominance variance components.</p> <p>Results</p> <p>Areas of two chromosomes were identified as suggestive of linkage to SBP and 5 areas to DBP in either the overall or sex specific analyses. The strongest evidence for linkage in the overall sample was to Chromosome 18q12 (LOD = 2.6 DBP). Sex specific analyses identified a linkage on Chromosome 4p12-14 (LOD in men only = 3.4 SBP). At Chromosome 2q32-33, an area where we previously reported significant evidence for linkage to DBP using a conventional identity by descent approach, the LOD was 1.4; however an appreciable sex effect was observed with men accounting for most of the linkage (LOD in men only = 2.6).</p> <p>Conclusion</p> <p>These results add evidence to a sex specific genetic architecture to blood pressure related traits, particularly in regions of linkage on chromosome 2, 4 and 18.</p