mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species

Reconstructions of the human-African great ape phylogeny by using mitochondrial DNA (mtDNA) have been subject to considerable debate. One confounding factor may be the lack of data on intraspecific variation. To test this hypothesis, we examined the effect of intraspecific mtDNA diversity on the phylogenetic reconstruction of another Plio- Pleistocene radiation of higher primates, the fascicularis group of macaque (Macaca) monkey species. Fifteen endonucleases were used to identify 10 haplotypes of 40-47 restriction sites in M. mulatta, which were compared with similar data for the other members of this species group. Interpopulational, intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of divergence time and branching order incorporating this variation were substantially different from those based on single representatives of each species. We conclude that intraspecific mtDNA diversity is substantial in at least some primate species. Consequently, without prior information on the extent of genetic diversity within a particular species, intraspecific variation must be assessed and accounted for when reconstructing primate phylogenies. Further, we question the reliability of hominoid mtDNA phylogenies, based as they are on one or a few representatives of each species, in an already depauperate superfamily of primates.      

Assessment of Effects of the OPRD1 and OPRM1 Genes Encoding Opioid Receptors on Apathy in Schizophrenia

Russian Journal of Genetics - Because of the involvement in motivational processes, opioid receptors are potential targets for apathy treatment in schizophrenia. We therefore searched for...     

Allele polymorphism of the serotonin transporter gene and clinical heterogeneity of depressive disorders

Depression disorders are a clinically heterogeneous disease group. Their development is to a substantial extent underlain by dysfunction of the serotonin system, in particular, disturbed serotonin transport. The heterogeneity of depressions is associated, among other factors, with the age at disease onset. Allele polymorphism of the serotonin transporter (5-HTT) gene was tested for association with age at disease onset, clinical signs, and anxiety-related traits of depression patients. A sample included 77 patients (mean age 61.2 +/- 8.8 years) with late-onset depression (LOD, mean age at onset 56.58 +/- 9.7 years) and 74 patients (mean age 31.0 +/- 11.8 years) with early-onset depression (EOD, mean age at onset 23.9 +/- 7.4 years). In genotype frequency distribution of two 5-HTT gene polymorphism, the LOD and EOD groups did not differ from each other (chi 2 = 0.33, P = 0.85 for VNTR-17; chi 2 = 3.33, P = 0.19 for HTTLPR) and from a control group (chi 2 = 0.34, P = 0.84 for VNTR-17; chi 2 = 2.1, P = 0.35 for HTTLPR). In either group, patients differing in VNTR-17 and HTTLPR genotypes did not differ in psychological traits and, in particular, in anxiety-related traits. In the case of the HTTLPR polymorphism, LOD patients with genotype ss tended to display less severe neuroticism (t = 2.03, P = 0.0507) and scored significantly less on the Hamilton depression scale (t = 2.19, P = 0.039). Thus, the 5-HTT gene polymorphisms do not affect the risk of depression but is possibly associated with specific clinical signs of the disease, at least in elderly patients.     

Changes in the EEG spectral power during perception of neutral and emotionally salient words in schizophrenic patients, their relatives and healthy individuals from the general population

To search for EEG-correlates of emotional processing that might be indicators of genetic predisposition to schizophrenia, changes in EEG spectral power during perception of neutral and emotionally salient words were examined in 36 schizophrenic patients, 50 of their unaffected first-degree relatives, and 47 healthy individuals without any family history of psychoses. In healthy persons, passive listening to neutral words induced minimum changes in cortical rhythmical activity, predominantly in the form of synchronization of slow and fast waves, whereas perception of emotional words was followed by a generalized depression of the alpha and beta1 activity and a locally specific decrease in the power of theta and beta2 frequency bands. The patients and their relatives showed a decrease in the alpha and beta1 activity simultaneously with an increase in the power of delta activity in response to both groups of words. Thus, in the patients and their relatives, reactions to neutral and emotional words were ulterior as a result of augmented reactions to the neutral words. These findings suggest that the EEG changes reflect familial and possibly hereditable abnormal involuntary attention. No prominent decrease in reactivity to emotional stimuli was revealed in schizophrenic families.     

Dopamine system genes and personality traits of extraversion and novelty seeking

Dopamine neurotransmissin is thought to play a relevant role in behavioral reinforcement system. Polymorphism of the genes involved in dopamine system has been reported for association with psychological traits related to impulsive and sensation seeking behaviors. The study was aimed at a search for association of catechol-O-metyltransferase (COMT) and dopamine receptor D4 (DRD4) gene polymorphism with personality traits in Russian population. A sample comprised 130 subjects. It was found that carriers of the Met/Met COMT genotype had higher scores of novelty seeking as compared to those with the Val/Val and Met/Met genotypes. The association was observed in women only. In the presence of the C allele of the DRD4 gene, females with the Met/Met genotype demonstrated higher scores on extraversion and hypomania. The results are consistent with the current theoretical concepts on the regulation of dopamine neurotransmission in the brain.     

Insertion/Deletion Polymorphism of the Serotonin Transporter Gene and Neuroticism as a Temperament Trait in Affective Patients and Healthy Individuals

Some studies associate the insertion/deletion polymorphism of the serotonin transporter (5-HTT) gene with anxiety-related personality traits in mentally healthy people, the short (s) allele being associated with a higher neuroticism score. The 5-HTT genotype and neuroticism score were established for 114 affective patients, 87 healthy relatives of endogenous psychosis patients, and for 156 mentally healthy people without familial psychiatric history. The effects of sex and age on the association between the two parameters was studied. Neuroticism proved to be not associated with the 5-HTT genotype.     

Analysis of the association of interleukin 4 and interleukin 10 gene variants with basic personality traits

There is growing evidence that serum levels of various inflammation markers are associated with personality traits. However, only few studies investigated the link between genetic variants of cytokine encoding genes and psychological characteristics. In this study, we examined genotypes in 297 individuals to assess the association between common variants of interleukin 4 (IL-4) and interleukin 10 (IL-10) genes and basic personality traits of extraversion and neuroticism, measured using the Eysenck Personality Questionnaire (EPQ). We found that, in homozygous female carriers of high expression alleles Т (IL-4 C-589T) and G (IL-10 G-1082A), neuroticism scores were higher (p = 0.045 and p = 0.08, respectively). In turn, extraversion scores were significantly higher in both male and female carriers of heterozygous variants CT and GA (p = 0.01). Our results are in accordance with the behavioral immune system hypothesis, and the general paradigm on the role of personality traits in health and longevity.     

An invisible ubiquitin conformation is required for efficient phosphorylation by PINK1

The Ser/Thr protein kinase PINK1 phosphorylates the well‐folded, globular protein ubiquitin (Ub) at a relatively protected site, Ser65. We previously showed that Ser65 phosphorylation results in a conformational change in which Ub adopts a dynamic equilibrium between the known, common Ub conformation and a distinct, second conformation wherein the last β‐strand is retracted to extend the Ser65 loop and shorten the C‐terminal tail. We show using chemical exchange saturation transfer (CEST) nuclear magnetic resonance experiments that a similar, C‐terminally retracted (Ub‐CR) conformation also exists at low population in wild‐type Ub. Point mutations in the moving β5 and neighbouring β‐strands shift the Ub/Ub‐CR equilibrium. This enabled functional studies of the two states, and we show that while the Ub‐CR conformation is defective for conjugation, it demonstrates improved binding to PINK1 through its extended Ser65 loop, and is a superior PINK1 substrate. Together our data suggest that PINK1 utilises a lowly populated yet more suitable Ub‐CR conformation of Ub for efficient phosphorylation. Our findings could be relevant for many kinases that phosphorylate residues in folded protein domains.     

Association of the insulin-like growth factor II (IGF2) gene with human cognitive functions

Active search for candidate genes whose polymorphisms are associated with human cognitive functions has been in progress in the past years. The study focused on the role that the insulin-like growth factor II (IGF2) gene may play in the variation of cognitive processes related to executive functions. The ApaI polymorphism of the IGF2 gene was tested for association with selective attention during visual search, working memory/mental control, and semantic verbal fluency in a group of 182 healthy individuals. The ApaI polymorphism was associated with the general cognitive index and selective attention measure. Carriers of genotype AA displayed higher values of the two parameters than carriers of genotype GG. It was assumed that the ApaI polymorphism of the IGF2 gene influences the human cognitive functions, acting possibly via modulation of the IGF-II level in the central nervous system.