![]() I then sampled all individuals of each shade-tolerant species in a 1-ha plot, and of each light-demanding species in 25 × 35-m plot, to estimate the frequency of asexual recruitment in natural populations using a series of different thresholds including the threshold set with the preliminary sampling. I sampled multiple ramets per individual from widely distributed plants for each of the five Piper species to set a threshold at the point where the error rate of clonal assignments was lowest. Here, I determine the consistency of the clonal threshold across five species in the tropical plant genus Piper, and evaluate the sensitivity of genetic diversity indices and estimates of frequency of clonal reproduction to the threshold value selected. Most studies to date have reported threshold values between 2% and 4%. Pairwise AFLP distances that distinguish known clones from nonclones have been used to identify a threshold genetic dissimilarity distance below which samples are considered to represent a single clone. We hypothesize that maintenance of genetic diversity and superior colonizing abilities of apomicts in temporally and spatially heterogeneous environments are important for their distributional success.Īmplified fragment length polymorphism (AFLP) has been widely used for clone identification, but numerous studies have shown that clonemates do not always present identical AFLP fingerprints. Habitat differentiation and a tendency to inhabit artificial meadows is more pronounced in apomictic than in sexual populations. Genetic diversity is partitioned mainly among apomictic populations and is not geographically structured, which may be due to facultative sexuality and/or multiple colonizations of sites by different clones. Two microsatellite loci discriminated genotypes separated by the accumulation of few mutations (‘clone mates’) within each AFLP clone. This local facultative sexuality may have a great impact on regional genotypic diversity. genotype/genodive and character incompatibility analyses suggest that genotypic variation within apomictic populations is caused by mutations, but in one population probably also by recombination. Polyploid populations consist either of a single AFLP genotype or of one dominant and a few deviating genotypes. Whereas two diploid populations showed high levels of genetic diversity, as expected for sexual reproduction, eight populations are hexaploid and harbour lower degrees of genotypic variation, but maintain high levels of heterozygosity at many loci, as is typical for apomicts. Population studies (amplified fragment length polymorphisms, microsatellites) and karyological methods (Feulgen DNA image densitometry and flow cytometry) were employed for characterization of genetic diversity and ploidy levels of 10 populations of Ranunculus carpaticola in central Slovakia. These transcripts might be useful biomarkers for evaluating the efficacy of IFN treatment of the MS patients.Sources and implications of genetic diversity in agamic complexes are still under debate. This study shows for the first time that a comparison of the relative quantitative expression of three different STAT genes in the blood cells of MS patients compared to controls revealed marked differences in the expression of the STAT family genes that might reflect their different roles in the pathogenesis of MS. In addition, there was no significant correlation between the expression of STAT1, STAT2, STAT3 genes and clinical findings, such as the level of physical disability in MS patients (according to the Kurtzke Expanded Disability Status Scale (EDSS) criterion) and disease duration.Ī significant positive correlation was demonstrated between STAT1 and STAT2 and also between STAT1 and STAT3. On the other hand, there was no significant difference between MS patients and controls for STAT3 gene expression (p= 0.837). The results showed that STAT1 gene expression was significantly up-regulated (p= 0.023), whereas STAT2 gene expression was significantly down-regulated (p< 0.0001) in MS patients compared to controls. This study aimed to assess STAT1, STAT2 and STAT3 gene expression in the blood of 50 relapsing-remitting MS (RR-MS) patients and 50 healthy controls by TaqMan Quantitative Real-Time PCR. The signal transducer and activator of transcription (STAT) family has an essential role in transmitting many of the cytokine-mediated signals and failure in the signaling process contributes to the etiopathogenesis of MS. Multiple sclerosis (MS) is the most common chronic, inflammatory, autoimmune disease of the central nervous system (CNS) maintained by the secretion of a large number of cytokines. ![]()
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