DNA Barcoding Study of Representative Thymus Species in Bulgaria.

We present a study on the taxonomy of eleven Thymus species, belonging to two sections and occurring naturally in Bulgaria. Four DNA barcoding markers-matK, rbcL, trnH-psbA and ITS-were applied to discriminate the species and to reveal their phylogenetic relationships. The results showed that rbcL has the lowest discriminating power regarding the studied species, while the other markers yielded results fitting better to the existing taxonomic schemes based on morphological traits. However, even in the case of better performing markers, the results were not straightforward-morphologically distinct species belonging to different sections were grouped together, and closely related species appeared genetically distinct. The results are typical for taxonomically complex groups, such as the genus Thymus, characterized in Bulgaria with great diversity, high percentage of endemism and still requiring a full and comprehensive taxonomic study. The results are discussed in the light of unresolved taxonomic problems and application of DNA barcoding methods.

Decreased FMR1 mRNA levels found in men with substance use disorders.

FMR1 gene (fragile X mental retardation 1) represents a genetic and epigenetic factor in a number of human diseases. Though the role of FMR1 gene in substance use disorders (SUDs) is not well studied, a number of investigations indicate that SUDs and FMR1-accociated disorders may share common underlying mechanisms. We examined the relative FMR1 mRNA levels and their sex-distribution in leukocytes from patients with alcohol and drug dependence compared to healthy controls. The study included 44 participants, 16 with alcohol dependence (mean age 43, 10 males and 6 females), 17 with drug dependence (mean age 41, 12 males and 5 females) and 11 healthy controls (mean age 47, 5 males and 6 females). Participants donated 5-6 ml of blood and completed a specialized questionnaire. Total RNA was isolated and cDNA was synthesized and used as a template for qRT-PCR analysis. The studied persons with alcohol and drug dependence share common socio-demographic and substance-use related characteristics. Significant FMR1 down-regulation was observed in the alcohol dependent group (25 % decrease; p = 0.005). Sex-associated analysis revealed that FMR1 down-regulation was primarily in alcohol-dependent men (40% decrease; p = 0.001) and did not reach significance in women. A similar sex-dependent pattern was observed among drug-dependent individuals. Drug-dependent men had significantly lower FMR1 mRNA levels (24% decrease; p = 0.015) compared with controls, while no significant difference was observed in drug-dependent females. These data indicate FMR1 mRNA down-regulation in persons with alcohol- and drug-dependence, relative to controls, is sex-dependent. This implies a role for FMR1 in substance use disorders. These findings require confirmation by including protein measures and the recruitment of larger cohorts.