rDNA Methylation in Hypericum perforatum Diploids and Tetraploids

The effect of the gene dosage on the expression of rRNAs was studied in Hypericum perforatum. The methylation levels of rDNA were analysed using the isoschizomers MspI and HpaII and eleven additional methylation-sensitive enzymes. No differences in rDNA methylation were observed between diploids and tetraploids at an early ontogenetic stage.

[Relationship of the CDKAL1 and KCNQ1 gene polymorphisms to the age at diagnosis of type 2 diabetes in the Slovakian population]

BACKGROUND/AIMS

The association of CDKAL1 and KCNQ1 genes with type 2 diabetes mellitus (DM2T) was confirmed by several genome-wide association studies in both Caucasian and Asian populations. For both genes, it is supposed that the risk of DM2T development is related to impaired insulin secretion. Based on assumption that the presence of risk allele might predispose to an earlier onset of DM2T, the aim of the present study was to assess the frequency of risk alleles of CDKAL1 rs7756992 and KCNQ1 rs163184 polymorphisms and to analyze their association with the age at DM2T diagnosis in the Slovakian population.

METHODS

CDKAL1 rs7756992 A/G and KCNQ1 rs163184 G/T polymorphisms were genotyped using asymmetric PCR with subsequent melting curve analysis in a group of 538 patients with DM2T. Anthropometric and laboratory parameters were determined by using standard methods. Since two genes were analysed, the required level for statistical significance was defined as p < 0.025.

RESULTS

Risk homozygotes (CG) for KCNQ1 polymorphism had higher mean age of DM2T diagnosis by 2 years when compared to T-allele carriers (GT + TT) in a recessive model, but the difference did not reach the predefined level of statistical significance. No relationship of CDKAL1 polymorphism to the age at onset of DM2T diagnosis was observed.

CONCLUSIONS

In the present study, no relationship of CDKAL1 and KCNQ1 polymorphisms to the earlier onset of type 2 diabetes was observed.

Epigenetic studies in human diseases

Irreversible genetic alterations underlying human diseases have been widely studied to date. However, it is evident that the potentially reversible epigenetic dysregulations may also have an important role in the disease origin. The studies of epigenetic mechanisms underlying disease onset, progression and pathogenesis have been performed in various human disorders. The epigenetic approaches may reveal useful markers for disease diagnostics, classification and prognostics as well as for progressive pharmacological treatment. This review summarizes the studies of epigenetic dysregulations including aberrant methylation, histone modifications and miRNA alterations in cancer as well as the studies of methylation changes and aberrant histone modifications in neurodegenerative, autoimmune, cardiovascular and other diseases. The imprinting disorders together with the emerging role of epigenetics in nutritional genomics, environment-organism interaction studies and in some other fields are also mentioned.