Assessment of genetic variability in captive capuchin monkeys (Primates: Cebidae).

Capuchin monkeys (genera Cebus and Sapajus) show a wide range distribution, from Honduras to Argentina. The aim of this work was to evaluate the genetic and phenotypic variability of captive specimens putatively belonging to S. cay (SCY) and S. nigritus (SNI) at their southernmost distribution limit. Forty-four individuals held in five captive centers from Argentina were analyzed based on external morphology, karyology and DNA sequences of mitochondrial control region (mtDNA-CR). Three morphotypes associated with their probable geographical origin in SCY and a single morphotype in SNI were found. For SCY we could associate each morphotype with the most frequent karyotype. SNI showed a single phenotype and a homogenous karyotype. Heterochromatin showed geographical patterns within species. A 515-bp mtDNA-CR fragment was sequenced, defining fourteen haplotypes at 59 polymorphic sites. A network constructed with our 14 haplotypes and other 77 from S. apella, S. macrocephalus, S. cay and S. nigritus from bibliography revealed some phylogeographic signals. Our SCY and SNI samples rendered four groups that differed in multiple mutational steps, with SCY being more similar to S. apella than to S. macrocephalus. Also, we identified two genetic divergent SCY groups: samples from NOA and from NEA with high mitochondrial diversity. Our results highlight the relevance of using complementary genetic tools throughout the distribution ranges of SCY and SNI for a better assessment of their diversity.

Introducción a la neurobiología y neurofisiología del trastorno del espectro autista / Introduction to the neubiology and neurofisiology of the autism spectrum disorder

Cuando se altera el cerebro humano en desarrollo y se produce una disfunción cognitiva, neurológica o psiquiátrica, se originan los Trastornos del Neurodesarrollo, teniendo el Trastorno del Espectro Autista (TEA) un lugar destacado. La prevalencia del TEA es de 1 cada 68 niños, aunque se discuten las variaciones dependiendo la región y la forma de medición. Esta revisión comprende, en parte, las principales características y problemáticas alrededor del desarrollo biológico del cerebro desde el punto de vista genético. Sin embargo, es destacable el factor ambiental incidente de los genes, que tiene influencia pequeña a moderada, aunque a la hora de marcar un desencadenante genético o ambiental clave, existe una gran heterogeneidad etiológica del TEA. Por otra parte, en este trabajo se abarcarán cambios estructurales y funcionales en el sistema nervioso central, analizando las características neurofisiológicas y morfológicas que intervienen enel trastorno. Así mismo, se analizan los avances de los resultados actuales en investigación que tratan de dar luz sobre la etiología del TEA e identificar soluciones específicas a las deficiencias cognitivas que éste produce. En conclusión, esta revisión destaca cómo ciertas anormalidades no conocidas previamente, y que incluso cambian los paradigmas con respecto a lo que sabemos sobre la neurobiología de los TEA, son marcadas como punto de partida para profundizar nuestro conocimiento.

In the human brain, alterations occur during the neurodevelopmental stages that are associated to cognitive, neurologic and psychiatric dysfunctions, are known as neurodevelopmental disorders. The Autistic Spectrum Disorder (ASD) is listed prominently in this group, since 1 out 68 kids are affected, although this prevalence changes among regions and type of measurement. This review encompasses, in part, the main features and problems about the biological development of the brain from a genetic point of view. However, it is noteworthy that the environmental factor has little to moderate influence, although it is difficult to find a key genetic or environmental factor to trigger the etiological heterogeneity seen in ASD. Moreover, this study covers structural and functional changes in the central nervous system analyzing the neurophysiological and morphological characteristics that are taken over by the disorder. Recent updates in ASD research regarding both the etiological and specific solutions to the cognitive deficiencies of the disorder are also reviewed here. Here we present the highlights to how certain abnormalities, not previously associated to the neurobiology of ASD, represent a starting point to deepen our knowledge of this disorder.

Association between GABA(A) receptor subunit polymorphisms and autism spectrum disorder (ASD).

ASD might be associated with alterations in excitation/inhibition ratio and GABA(A) has been implicated since it mediates synaptic inhibition. Polymorphisms in GABA receptor (GABAR) were studied: significant differences in allele and genotype frequencies observed between cases and controls (rs1912960, GABRA4). Haplotype analysis: rs1912960 (GABRA4) and rs211037 (GABRG2) overrepresented in cases. Rs1912960 has been associated with ASD and rs211037 with epilepsy. GABRA4 is associated with autism in the Argentinean dataset independently or in combination with GABRG2.

Evidence for interaction between markers in GABA(A) receptor subunit genes in an Argentinean autism spectrum disorder population.

Autism spectrum disorders (ASD) can be conceptualized as a genetic dysfunction that disrupts development and function of brain circuits mediating social cognition and language. At least some forms of ASD may be associated with high level of excitation in neural circuits, and gamma-aminobutyric acid (GABA) has been implicated in its etiology. Single-nucleotide polymorphisms (SNP) located within the GABA receptor (GABAR) subunit genes GABRA1, GABRG2, GABRB3, and GABRD were screened. A hundred and thirty-six Argentinean ASD patients and 150 controls were studied, and the contribution of the SNPs in the etiology of ASD was evaluated independently and/or through gene-gene interaction using multifactor dimensionality reduction (MDR) method. From the 18 SNP studied, 11 were not present in our Argentinean population (patients and controls) and 1 SNP had minor allele frequency < 0.1%. For the remaining six SNPs, none provided statistical significant association with ASD when considering allelic or genotypic frequencies. Non-significant association with ASD was found for the haplotype analysis. MDR identified evidence for synergy between markers in GABRB3 (chromosome 15) and GABRD (chromosome 1), suggesting potential gene-gene interaction across chromosomes associated with increased risk for autism (testing balanced accuracy: 0.6081 and cross-validation consistency: 10/10, P < 0.001). Considering our Argentinean ASD sample, it can be inferred that GABRB3 would be involved in the etiology of autism through interaction with GABRD. These results support the hypothesis that GABAR subunit genes are involved in autism, most likely via complex gene-gene interactions.

[Non invasive prenatal diagnosis. Fetal nucleic acid analysis in maternal blood]. / Diagnóstico prenatal no invasivo. Acidos nucleicos de origen fetal en sangre materna.

Current prenatal diagnosis of monogeneic and chromosomal diseases, includes invasive procedures which carry a small but significant risk. For many years, analysis of fetal cells in maternal circulation has been studied, however it has failed its clinical use due to the scarcity of these cells and their persistance after delivery. For more than a decade, the presence of cell-free fetal DNA in maternal blood has been identified. These fetal DNA fragments would derive from the placenta and are not detected after delivery, making them a source of fetal material for carrying out diagnosis techniques using maternal blood. However, the vast majority of cell free DNA in maternal circulation is of maternal origin, with the fetal component contributing from 3% to 6% and rising towards term. Available methodologies do not allow separation of fetal from maternal cell free DNA, so current applications have been focused on the analysis of genes not present in the mother, such as Y chromosome sequences, or RHD gene in RhD-negative women, or paternal or de novo mutations. Also, the detection of cell-free fetal RNA in maternal blood offers the possibility of obtaining information regarding genetic expression profiles of embrionic tissues, and using genes expressed only at the feto-placental unit, controls for the presence of fetal material could be established, regardless of maternal genetic tissue. The present article describes the evidences regarding the passage of fetal nucleic acids to maternal circulation, its current prenatal diagnosis application and possible future perspectives.

Diagnóstico prenatal no invasivo: Ácidos nucleicos de origen fetal en sangre materna / Non invasive prenatal diagnosis: Fetal nucleic acid analysis in maternal blood

Las técnicas actuales de diagnóstico prenatal de enfermedades génicas y cromosómicas incluyen procedimientos invasivos que conllevan un pequeño, pero significativo, riesgo. Por muchos años se ha estudiado la posibilidad de utilizar células fetales en circulación materna; sin embargo, ha fracasado su implementación clínica debido a su escasez y persistencia luego del parto. Desde hace más de una década se detectó ADN fetal libre en sangre de embarazadas. Este sería de origen placentario e indetectable después del parto, y fuente de material fetal para el desarrollo de técnicas diagnósticas utilizando sangre materna. No obstante, la mayoría del ADN libre en circulación materna es de origen materno con una contribución fetal del 3% al 6% aumentando a lo largo de la gestación. Dado que los métodos actuales no permiten separar el ADN libre fetal del materno, las aplicaciones se focalizan en el análisis de genes no presentes en la madre, tales como secuencias del cromosoma Y, o gen RHD en madres Rh negativas, o mutaciones paternas o de novo. Asimismo, la detección de ARN fetal libre en sangre de embarazadas abrió la posibilidad de obtener información acerca de patrones de expresión génica de tejidos embrionarios y, utilizando genes que se expresan sólo en la unidad feto-placentaria, se podría establecer un control de presencia de material fetal, independiente del material genético de la madre. El presente trabajo describe las evidencias acerca del pasaje de ácidos nucleicos fetales a circulación materna, su aplicación actual en el diagnóstico prenatal y posibles usos futuros.

Current prenatal diagnosis of monogeneic and chromosomal diseases, includes invasive procedures which carry a small but significant risk. For many years, analysis of fetal cells in maternal circulation has been studied, however it has failed its clinical use due to the scarcity of these cells and their persistance after delivery. For more than a decade, the presence of cell-free fetal DNA in maternal blood has been identified. These fetal DNA fragments would derive from the placenta and are not detected after delivery, making them a source of fetal material for carrying out diagnosis techniques using maternal blood. However, the vast majority of cell free DNA in maternal circulation is of maternal origin, with the fetal component contributing from 3% to 6% and rising towards term. Available methodologies do not allow separation of fetal from maternal cell free DNA, so current applications have been focused on the analysis of genes not present in the mother, such as Y chromosome sequences, or RHD gene in RhD-negative women, or paternal or de novo mutations. Also, the detection of cell-free fetal RNA in maternal blood offers the possibility of obtaining information regarding genetic expression profiles of embrionic tissues, and using genes expressed only at the feto-placental unit, controls for the presence of fetal material could be established, regardless of maternal genetic tissue. The present article describes the evidences regarding the passage of fetal nucleic acids to maternal circulation, its current prenatal diagnosis application and possible future perspectives.

[Non invasive prenatal genetic diagnosis of fetal RhD and sex through the analysis of free fetal DNA in maternal plasma]. / Diagnóstico genético prenatal no invasivo de factor Rh y sexo fetal a través del análisis de ADN fetal libre en plasma materno.

INTRODUCTION: The analysis of free fetal DNA in maternal plasma allows the assessment of fetal genetic material avoiding the necessity of invasive procedures during pregnancy. OBJECTIVE: To evaluate the feasibility and the diagnostic performance of fetal sex and fetal RhD detection through the analysis of free fetal DNA in maternal plasma using standard reagents in molecular biology. MATERIAL AND METHODS: A hundred and nine blood samples of pregnant women were obtained. Amplification by real time PCR a sequence from the RhD gene in Rh negative patients and a Y-chromosome sequence, for the diagnosis of fetal Rh and sex respectively, were performed. Results were compared with neonatal outcomes. RESULTS: From the 109 samples, 26 are still ongoing, 4 ended in spontaneous abortions and in 3 were lost to follow up. From the remaining 76 samples with neonatal result, the determination of fetal Rh from the RhD gene was performed in 65 Rh negative women, whereas in 66 samples the fetal sex analysis was evaluated. Overall, 15 samples had not conclusive results and were excluded from the study. The predictive values for RhD positive and negative were 85% and 90%, respectively, while the prediction for male sex was 94.3% and for female sex 95%. CONCLUSION: The non invasive determination of fetal RhD and sex in maternal plasma using standard reagents in molecular biology was feasible in the majority of the samples, with a diagnostic performance similar to the reported in the literature.

Diagnóstico genético prenatal no invasivo de factor Rh y sexo fetal a través del análisis de ADN fetal libre en plasma materno / Non invasive prenatal genetic diagnosis of fetal RhD and sex through the analysis of free fetal DNA in maternal plasma

Introducción. El análisis de ADN fetal libre en plasma materno permite estudiar material genético del feto sin realizar procedimientos invasivos sobre el embarazo. Objetivo. Evaluar la factibilidad y desempeño diagnóstico de la determinación del genotipo RhD y del sexo fetal a través del análisis molecularde ADN fetal libre en plasma de embarazadas mediante reactivos de uso general en biología molecular. Material y métodos. Se extrajeron 109 muestras de sangre de embarazadas. Se amplificó por PCR en tiempo real una porción del gen RhD para el diagnóstico de Rh fetal en mujeres Rh-negativas y una región del cromosoma Y para la determinación del sexo fetal. Ambos datos se compararon con los resultados neonatales. Resultados. Respecto de las 109 muestras, 26 embarazos están en curso, 4 tuvieron abortos espontáneos y en 3 se perdió el seguimiento. De las 76 restantes con resultado neonatal, en 65 mujeres Rh-negativas se efectuó el análisis del gen RhD para la determinación del Rh fetal y en 66 muestras se realizó la determinación del sexo fetal. Quince muestras fueron no concluyentes y se excluyeron del análisis. El valor predictivo para RhD-positivo y RhD-negativo fue 85 por ciento y 90%, respectivamente, mientras que la predicción de sexo masculino fue 94,3 por ciento y la del femenino 95 por ciento. Conclusiones. La determinación no invasiva del RhD y sexo fetal en plasma materno mediante reactivos de uso general en biología molecular fue factible en la mayoría de los casos, con un desempeño diagnóstico similar al descripto en la bibliografía.(AU)

Introduction. The analysis of free fetal DNA in maternal plasma allows the assessment of fetal genetic material avoiding the necessity of invasive procedures during pregnancy. Objective. To evaluate the feasibility and the diagnostic performance of fetal sex and fetal RhD detection through the analysis of free fetal DNA in maternal plasma using standard reagents in molecular biology. Material and methods. A hundred and nine blood samples of pregnant women were obtained obtained. Amplification by real time PCR a sequence from the RhD gene in Rh negative patients and a Y-chromosome sequence, for the diagnosis of fetal Rh and sex respectively, were performed. Results were compared with neonatal outcomes. Results. From the 109 samples, 26 are still ongoing, 4 ended in spontaneous abortions and in 3 were lost to follow up. From the remaining 76 samples with neonatal result, the determination of fetal Rh from the RhD gene was performed in 65 Rh negative women, whereas in 66 samples the fetal sex analysis was evaluated. Overall, 15 samples had not conclusive results and were excluded from the study. The predictive values for RhD positive and negative were 85 percent and 90 percent, respectively, while the prediction for male sex was 94.3 percent and for female sex 95 percent. Conclusion. The non invasive determination of fetal RhD and sex in maternal plasma using standard reagents in molecular biology was feasible in the majority of the samples, with a diagnostic performance similar to the reported in the literature.(AU)

Diagnóstico genético prenatal no invasivo de factor Rh y sexo fetal a través del análisis de ADN fetal libre en plasma materno / Non invasive prenatal genetic diagnosis of fetal RhD and sex through the analysis of free fetal DNA in maternal plasma

Introducción. El análisis de ADN fetal libre en plasma materno permite estudiar material genético del feto sin realizar procedimientos invasivos sobre el embarazo. Objetivo. Evaluar la factibilidad y desempeño diagnóstico de la determinación del genotipo RhD y del sexo fetal a través del análisis molecularde ADN fetal libre en plasma de embarazadas mediante reactivos de uso general en biología molecular. Material y métodos. Se extrajeron 109 muestras de sangre de embarazadas. Se amplificó por PCR en tiempo real una porción del gen RhD para el diagnóstico de Rh fetal en mujeres Rh-negativas y una región del cromosoma Y para la determinación del sexo fetal. Ambos datos se compararon con los resultados neonatales. Resultados. Respecto de las 109 muestras, 26 embarazos están en curso, 4 tuvieron abortos espontáneos y en 3 se perdió el seguimiento. De las 76 restantes con resultado neonatal, en 65 mujeres Rh-negativas se efectuó el análisis del gen RhD para la determinación del Rh fetal y en 66 muestras se realizó la determinación del sexo fetal. Quince muestras fueron no concluyentes y se excluyeron del análisis. El valor predictivo para RhD-positivo y RhD-negativo fue 85 por ciento y 90%, respectivamente, mientras que la predicción de sexo masculino fue 94,3 por ciento y la del femenino 95 por ciento. Conclusiones. La determinación no invasiva del RhD y sexo fetal en plasma materno mediante reactivos de uso general en biología molecular fue factible en la mayoría de los casos, con un desempeño diagnóstico similar al descripto en la bibliografía.

Introduction. The analysis of free fetal DNA in maternal plasma allows the assessment of fetal genetic material avoiding the necessity of invasive procedures during pregnancy. Objective. To evaluate the feasibility and the diagnostic performance of fetal sex and fetal RhD detection through the analysis of free fetal DNA in maternal plasma using standard reagents in molecular biology. Material and methods. A hundred and nine blood samples of pregnant women were obtained obtained. Amplification by real time PCR a sequence from the RhD gene in Rh negative patients and a Y-chromosome sequence, for the diagnosis of fetal Rh and sex respectively, were performed. Results were compared with neonatal outcomes. Results. From the 109 samples, 26 are still ongoing, 4 ended in spontaneous abortions and in 3 were lost to follow up. From the remaining 76 samples with neonatal result, the determination of fetal Rh from the RhD gene was performed in 65 Rh negative women, whereas in 66 samples the fetal sex analysis was evaluated. Overall, 15 samples had not conclusive results and were excluded from the study. The predictive values for RhD positive and negative were 85 percent and 90 percent, respectively, while the prediction for male sex was 94.3 percent and for female sex 95 percent. Conclusion. The non invasive determination of fetal RhD and sex in maternal plasma using standard reagents in molecular biology was feasible in the majority of the samples, with a diagnostic performance similar to the reported in the literature.

Molecular and morphometric variation in chromosomally differentiated populations of the grasshopper Sinipta dalmani (Orthopthera: Acrididae).

Sinipta dalmani is an Argentine grasshopper whose chromosome polymorphisms have been widely studied through cytogenetic, morphometric, and fitness component analyses. The present work analysed molecular and morphometric variation in seven chromosomally differentiated populations from Entre Rios and Buenos Aires provinces to analyse population structure. Molecular studies were performed studying RAPD loci and morphometric analyses were carried out measuring five morphometric traits. Genetic variability was high in all studied populations and was characterized by a decrease in H as a function of latitude and temperature. Both conventional F(ST) analysis and Bayesian approach for dominant marker showed that there were significant genetic differences among all populations, between provinces, and among populations within provinces. Entre Rios populations showed higher mean numbers of migrants per generation as well as low genetic differentiation and high gene flow with almost all populations whereas Buenos Aires populations may be considered as a result of a more recently colonization. There is considerable morphometric variation between populations and this variation correlates with latitude and temperature. Our results suggest that selection contributes to phenotypic differentiation among populations by moulding the differences in trait means whereas genetic drift is responsible for differences in the matrix of variance-covariance. The gene flow detected is insufficient to prevent phenotypic and chromosome divergences.