Natural accessions are used for studying intraspecies genetic variation in the model plant Arabidopsis thaliana in order to address fundamental questions of evolution. Transposable elements are responsible for a wide range of mutations and play significant roles in shaping a genome over evolutionary time. In the present study, we aimed to characterize ONSEN, a heat-activated long terminal repeat (LTR) retrotransposon, in natural A. thaliana accessions. Southern blot analysis demonstrated that ONSEN was present in all the studied accessions, but the copy number was diverse. Olympia-1 contained a single ONSEN copy, located in the centromere of Chromosome 3. A premature stop codon in Olympia-1 ONSEN presumably abolishes integrase activity, which in turn presumably renders the retrotransposon non-functional. Hybridization of Col-0 with Olympia-1 showed that several ONSEN copies in Col-0 were activated by heat stress and maintained their transpositional activity in the progeny.

Amyotrophic lateral sclerosis (ALS) is a multifactorial disease, possibly with contributions from genetics and lifestyle. We examined variants in genes relevant to energy metabolism and physical activity in a case-control association study, with the aim of assessing genetics and physical activity as contributors to ALS risk. A well-characterized sample of Italian ALS patients (101) and controls (101) from the EURALS Consortium underwent a questionnaire interview on demographic, physical and other lifestyle habits, and venipuncture for DNA extraction. The genes selected were sirtuin 3 (SIRT3), peroxisome proliferator-activated receptor-γ coactivator-1α (PPARGC1A) and apolipoprotein E (APOE). Genetic studies suggested, for the first time, a protective role of the SIRT3 single-nucleotide polymorphism rs4980329 in ALS risk, and a contribution of the APOE-ε2 allele, which was more frequent in ALS patients than in controls. A joint analysis coupling genetic data and sporting activity revealed opposite roles of APOE-ε2 and SIRT3 rs3825075, the former being more frequent in physically active ALS patients and the latter more frequent in physically inactive patients. These findings suggest a contribution to ALS risk of genetic and environmental factors involved in energy metabolism, and stress the importance of a multifactorial analysis for evaluating this risk.

Carrier frequency of the β^S allele has been reported to be 0.19% in Mazandaran province, northern Iran. Haplotype analysis of the β^S allele helps trace the origin of its encoded hemoglobin (Hb) variant, Hb S, in a region. The aim of this study was to investigate the haplotypes associated with β^S alleles in Mazandaran province. Capillary electrophoresis was carried out to detect individuals suspected to have a β^S allele(s). DNA analysis (PCR-RFLP) was used for final confirmation. To identify 5′ to 3′ β-globin gene cluster haplotypes associated with β^S alleles, family linkage analysis was applied. Six polymorphic sites (HincII 5′ to ε, XmnI 5′ to ^Gγ, HindIII in ^Gγ, HindIII in ^Aγ, HincII 3′ to ψβ and AvaII in β) were investigated using the PCR-RFLP method. Five different haplotypes were linked to β^S alleles, while β^A alleles were associated with nine haplotypes. Among the β^S alleles, 53.9% were associated with the Benin (----++) haplotype, and the Arab-Indian (+++-++) haplotype had the second-highest frequency (23%). Unlike southern provinces, where the Arab-Indian haplotype is prominent, the Benin haplotype is the most frequent haplotype in northern Iran, and this may represent a founder effect. Since the Benin haplotype does not carry the XmnI polymorphism 5′ to the ^Gγ gene, which is responsible for high expression of Hb F, a severe form of sickle cell disease can be anticipated in patients that are homozygous for the β^S allele in the northern region.