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Anna Székely

Publications and source records attributed to Anna Székely.

5 recordsLinked to original sources
PubMed2005

Observation of bias associated with re-amplification of DNA isolated from denaturing gradient gels.

DNA from environmental PCR products separated by denaturing gradient gel electrophoresis (DGGE) was isolated from the background smear rather than from discrete bands of the DGGE gel. The "interband" region was considered as a potential source of less dominant members of natural microbial communities. Surprisingly, instead of detecting new bands from the re-amplified PCR products, patterns very similar to the original ones were obtained regardless of the position of the "interband" region. The results suggest that the separation of amplicons by DGGE may not be perfect and band re-amplification based sequence analyses need careful interpretation.

DNA, Ribosomal↗
PubMed2005

["Persistence" as possible psychogenetic endophenotype].

For some human traits heritability estimates are well known based on results from twin studies. However, the study of connecting these characteristics to candidate genes in the Human Genome has just been started. The main goal of the recently formulated Human Fenom Project is to define "endophenotypes", characteristics that have considerable heritable component, and can be empirically measured with objective tools, standardized across cultures. Based on our recent findings the VNTR polymorphism in the coding region of the dopamine D4 receptor gene is a candidate gene of the "persistence" trait. Individuals carrying the 7-repeat polymorphism of this allele describe themselves as less persistent. In line with these results the 7-repeat polymorphism was associated to the "persistence" trait as measured by the Junior version of the TCI in a psychiatric sample of children diagnosed with ADHD. Based on these findings our main goal was to define an objective, behavioral measure which could be used as an "endophenotype" in genetic association studies. "Persistence" could be related to responsiveness in a reaction time task demanding sustained attention, for example. This hypothesis was tested using a sample of 35 healthy Caucasian subjects, participating in a extended cognitive reaction time task and filling out the TCI personality questionnaire. Non-invasive DNA sampling was used to determine the candidate polymorphism of the DRD4-VNTR. Results using self-report data replicated our previous findings: the 7-repeat polymorphism was significantly associated to lower "persistence" scores. Individual differences of reaction time were compared using the 7-repeat present/absent grouping as well. Results indicate that responses of individuals with the 7-repeat allele were significantly slower and more variable than of those without this candidate allele. Based on self-report and behavioural measures "persistence" trait is a possible endophenotype of psychogenetic associations.

Character↗
PubMed2005

Combined effect of promoter polymorphisms in the dopamine D4 receptor and the serotonin transporter genes in heroin dependence.

Dopamine D4 receptor (DRD4) and serotonin transporter (SERT) gene polymorphisms were studied, as possible genetic risk factors for substance dependence. The case-control study involved a large cohort (n = 362) of healthy Caucasian population, and an initial sample of 73 substance dependent patients (including a subgroup of 53 heroin dependents). Improved methods were applied for genotype detection of the DRD4 polymorphisms (exon 3 48 bp VNTR; -521 C/T SNP and 120 bp duplication in the 5' flanking region) and the SERT gene polymorphisms (5-hydroxytriptamin transporter linked polymorphic region [5-HTTLPR] in the 5' flanking region and the intron 2 VNTR [STin2]). Association between the -521 C/T SNP of the DRD4 promoter region and substance dependence was significant in the subgroup of heroin dependents (p = 0.044). The other analyzed polymorphisms did not show any significant association, but an interaction between -521 C/T SNP of DRD4 and the 5-HTTLPR polymorphisms was observed. Association between the -521 CC vs. CT or TT genotypes and heroin dependence was enhanced in the presence of short (s or 14-repeat) 5-HTTLPR allele (p 0.01). The odds ratio of 2.14 observed for the -521 CC genotype increased to 4.82 in double homozygotes of -521 CC and 5-HTTLPR ss, emphasizing the importance of combined analysis of polymorphisms in the dopaminergic and serotonergic systems in heroin dependence. However, due to the limited size of our sample these results should be interpreted with caution.

Adolescent↗
PubMed2003

Timed picture naming in seven languages.

Timed picture naming was compared in seven languages that vary along dimensions known to affect lexical access. Analyses over items focused on factors that determine cross-language universals and cross-language disparities. With regard to universals, number of alternative names had large effects on reaction time within and across languages after target-name agreement was controlled, suggesting inhibitory effects from lexical competitors. For all the languages, word frequency and goodness of depiction had large effects, but objective picture complexity did not. Effects of word structure variables (length, syllable structure, compounding, and initial frication) varied markedly over languages. Strong cross-language correlations were found in naming latencies, frequency, and length. Other-language frequency effects were observed (e.g., Chinese frequencies predicting Spanish reaction times) even after within-language effects were controlled (e.g., Spanish frequencies predicting Spanish reaction times). These surprising cross-language correlations challenge widely held assumptions about the lexical locus of length and frequency effects, suggesting instead that they may (at least in part) reflect familiarity and accessibility at a conceptual level that is shared over languages.

Cross-Cultural Comparison↗