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Genetic Distinctions (genetic + distinction)
Selected AbstractsEvidence of genetic distinction and long-term population decline in wolves (Canis lupus) in the Italian ApenninesMOLECULAR ECOLOGY, Issue 3 2004V. Lucchini Abstract Historical information suggests the occurrence of an extensive human-caused contraction in the distribution range of wolves (Canis lupus) during the last few centuries in Europe. Wolves disappeared from the Alps in the 1920s, and thereafter continued to decline in peninsular Italy until the 1970s, when approximately 100 individuals survived, isolated in the central Apennines. In this study we performed a coalescent analysis of multilocus DNA markers to infer patterns and timing of historical population changes in wolves surviving in the Apennines. This population showed a unique mitochondrial DNA control-region haplotype, the absence of private alleles and lower heterozygosity at microsatellite loci, as compared to other wolf populations. Multivariate, clustering and Bayesian assignment procedures consistently assigned all the wolf genotypes sampled in Italy to a single group, supporting their genetic distinction. Bottleneck tests showed evidences of population decline in the Italian wolves, but not in other populations. Results of a Bayesian coalescent model indicate that wolves in Italy underwent a 100- to 1000-fold population contraction over the past 2000,10 000 years. The population decline was stronger and longer in peninsular Italy than elsewhere in Europe, suggesting that wolves have apparently been genetically isolated for thousands of generations south of the Alps. Ice caps covering the Alps at the Last Glacial Maximum (c. 18 000 years before present), and the wide expansion of the Po River, which cut the alluvial plains throughout the Holocene, might have provided effective geographical barriers to wolf dispersal. More recently, the admixture of Alpine and Apennine wolf populations could have been prevented by deforestation, which was already widespread in the fifteenth century in northern Italy. This study suggests that, despite the high potential rates of dispersal and gene flow, local wolf populations may not have mixed for long periods of time. [source] Genetic Data and the Listing of Species Under the U.S. Endangered Species ActCONSERVATION BIOLOGY, Issue 5 2007SYLVIA M. FALLON Acta de Especies en Peligro de E. U. A.; decisiones de enlistado; segmento poblacional distinto Abstract:,Genetic information is becoming an influential factor in determining whether species, subspecies, and distinct population segments qualify for protection under the U.S. Endangered Species Act. Nevertheless, there are currently no standards or guidelines that define how genetic information should be used by the federal agencies that administer the act. I examined listing decisions made over a 10-year period (February 1996,February 2006) that relied on genetic information. There was wide variation in the genetic data used to inform listing decisions in terms of which genomes (mitochondrial vs. nuclear) were sampled and the number of markers (or genetic techniques) and loci evaluated. In general, whether the federal agencies identified genetic distinctions between putative taxonomic units or populations depended on the type and amount of genetic data. Studies that relied on multiple genetic markers were more likely to detect distinctions, and those organisms were more likely to receive protection than studies that relied on a single genetic marker. Although the results may, in part, reflect the corresponding availability of genetic techniques over the given time frame, the variable use of genetic information for listing decisions has the potential to misguide conservation actions. Future management policy would benefit from guidelines for the critical evaluation of genetic information to list or delist organisms under the Endangered Species Act. Resumen:,La información genética se está convirtiendo en un factor influyente para determinar sí una especie, subespecie y segmentos poblacionales distintos califican para ser protegidos por el Acta de Especies en Peligro de E. U. A. Sin embargo, actualmente no hay estándares o lineamientos que definan como deben utilizar información genética las agencias federales que administran el acta. Examiné las decisiones de enlistado basadas en información genética tomadas en un período de 10 años (febrero 1996,febrero 2006). Hubo una amplia variación en los datos genéticos utilizados para informar las decisiones de enlistado en términos de cuáles genomas (mitocondrial vs. nuclear) fueron muestreados y el número de marcadores (o técnicas genéticas) y los loci evaluados. En general, las agencias federales identificaron diferencias genéticas entre unidades taxonómicas putativas o poblaciones dependiendo del tipo y cantidad de datos genéticos. Los estudios que se basaron en marcadores genéticos múltiples tuvieron mayor probabilidad de identificar distinciones, y esos organismos tuvieron mayor probabilidad de recibir protección, que los estudios basados en un solo marcador genético. Aunque los resultados pueden, en parte, reflejar la disponibilidad de técnicas genéticas para decisiones de enlistado en el período analizado, el uso variable de información genética para la toma de decisiones puede desinformar acciones de conservación. Las políticas de manejo futuras se beneficiarían de directrices para la evaluación crítica de información genética para enlistar o quitar de la lista a organismos bajo el Acta de Especies en Peligro. [source] Neurophysiological and genetic distinctions between pure and comorbid anxiety disorders,DEPRESSION AND ANXIETY, Issue 5 2008Mary-Anne Enoch M.D. Abstract Anxiety disorders are often comorbid with major depression (MD) and alcohol use disorders (AUD). Two common functional polymorphisms in catechol-O-methyltransferase (COMT Val158Met) and brain-derived neurotrophic factor (BDNF Val66Met) genes have been implicated in the neurobiology of anxiety and depression. We hypothesized that attentional response and working memory (auditory P300 event-related potential and Weschler Adult Intelligence Scale, Revised digit symbol scores) as well as genetic vulnerability would differ between pure anxiety disorders and comorbid anxiety. Our study sample comprised 249 community-ascertained men and women with lifetime DSM-III-R diagnoses. We analyzed groups of participants with pure anxiety disorders, pure MD, pure AUD, comorbid anxiety, and no psychiatric disorder. Participants were well at the time of testing; state anxiety and depressed mood measures were at most only mildly elevated. Individuals with pure anxiety disorders had elevated P300 amplitudes (P=0.0004) and higher digit symbol scores (P<0.0001) compared with all the other groups. Individuals with comorbid anxiety had the greatest proportion of COMT Met158 and BDNF Met66 alleles (P=0.009) as well as higher harm avoidance-neuroticism (P<0.0005) than all other groups. Our results suggest that there may be two vulnerability factors for anxiety disorders with differing genetic susceptibility: (a) heightened attention and better working memory with mildly elevated anxiety-neuroticism, a constellation that may be protective against other psychopathology; and (b) poorer attention and working memory with greater anxiety-neuroticism, a constellation that may also increase vulnerability to AUD and MD. This refinement of the anxiety phenotype may have implications for therapeutic interventions. Depression and Anxiety 0:1,10, 2007. Published 2007 Wiley-Liss, Inc. [source] Induced and repressed genes after irradiation sensitizing by pentoxyphylline,INTERNATIONAL JOURNAL OF CANCER, Issue 6 2007Waldemar Waldeck Abstract Aim in cancer therapy is to increase the therapeutic ratio eliminating the disease while minimizing toxicity to normal tissues. Radiation therapy is a main component in targeting cancer. Radiosensitizing agents like pentoxyphylline (PTX) have been evaluated to improve radiotherapy. Commonly, cells respond to radiation by the activation of specific early and late response genes as well as by inhibition of genes, which are expressed under normal conditions. A display of the genetic distinctions at the level of transcription is given here to characterize the molecular events underlying the radiosensitizing mechanisms. The method of suppression subtractive hybridization allows the visualization of both induced and repressed genes in irradiated cells compared with cells sensitized immediately after irradiation. The genes were isolated by cDNA-cloning, differential analysis and sequence similarity search. Genes involved in protein synthesis, metabolism, proteolysis and transcriptional regulation were detected. It is important that genes like KIAA280, which were only known as unidentified EST sequences before without function, but inaccessible by array technology were recovered as functional genes. Database searches for PTX-induced genes detected a human mRNA completely unknown. In case of suppressed genes, we detected several mRNAs; one thereof shows homology to a hypothetical protein possibly involved in signal transduction. A further mRNA encodes the protein BM036 supposed to associate with the E2F transcription factor. A hypothetical protein H41 was detected, which may repress the Her-2/neu receptor influencing breast cancer, gliomas and prostate tumors. Radiation combined with PTX may lead to a better prognosis by down regulation of the Her-2/neu, which will be proven by clinical studies in the near future. © 2006 Wiley-Liss, Inc. [source] | |||||||||||||