Name: array comparative genomic hybridization (array cgh) for detection of genomic copy number variants
Uploaded: 2015-02-21T14:00:00.000+00:00
Duration: 9 min 16 s
Description: Watch this Scientific Journal Video about Array Comparative Genomic Hybridization Array CGH for Detection of Genomic Copy Number Variants at JoVE.com

The authors have no acknowledgements.

Reacción 1. El etiquetado <ol><li> Antes de su uso, dUTPs pre-alícuota cianina 3 y 5-etiquetados, nucleótidos no marcados y cebadores aleatorios en las concentraciones recomendadas por el fabricante en placas y tienda de 96 pocillos a -20 C listo para su uso. A los fines de este protocolo, alícuota 10,5 l de la dUTP etiquetado apropiado y 10,5 l nucleótidos no marcados y cebadores aleatorios a cada pocillo. </li><li> Descongelar la placa lista para el uso de 96 pocillos de nucleótidos y cebadores a 4 ° C durante aproximadamente 1 hora, protegido de la luz. </li><li> Una vez descongelado, esta placa de equilibrar a temperatura ambiente durante al menos 30 min, protegido de la luz. </li><li> Equilibrar muestras de ADN a 60 ° C durante al menos 15 min. </li><li> El uso de un robot de manejo de líquidos, dispensar agua libre de nucleasa a cada pocillo de una placa de 96 pocillos. NOTA: El volumen de agua dependerá de la concentración de cada muestra de ADN de entrada y debe ser suficiente para dar lugar a una concentración final de 50 ng / ul. </li><li> El uso de un líquido de hanrobot dling, pipeta de 1 g de ADN en un pocillo de la placa de 96 pocillos (véase 1.5) para llevar el volumen total a 20 l. NOTA: Pequeñas cantidades de ADN se pueden usar aunque la calidad de los datos resultantes puede verse comprometida (para muestras preciosas, cantidades de ADN de entrada abajo a 400 ng pueden ser utilizados). </li><li> El uso de un robot de manejo de líquidos, transferir 20 l de los nucleótidos y cebadores equilibradas en cada pocillo de la placa de DNA diluido. </li><li> Sellar la placa de 96 pocillos con tapas de la tira (un sello hermético es crucial). </li><li> Desnaturalizar el ADN a 99 ° C durante 10 min en una máquina de PCR con una tapa calentada y luego haga presión fría en hielo durante 5 min a cebadores de recocido. </li><li> El uso de un robot de manipulación de líquidos, añadir 10 l de ADN Exo Klenow enzima polimerasa de ADN y cada mezcla pipeta a fondo. NOTA: El volumen total debe ser de 50 l. </li><li> Sellar la placa de 96 pocillos y se incuba a 37 ° C durante 16 horas. NOTA: Una incubación más corto de 4 horas es suficiente, sin embargo un O / N enincubación puede ser más conveniente. </li><li> El uso de un robot de manejo de líquidos, añadir 5 l de tampón de parada a cada pocillo. NOTA: Un resumen de los reactivos utilizados para la reacción de marcaje se muestra en la Tabla 1. </li></ol> 2. La eliminación de nucleótidos no incorporados <ol><li> Retire los nucleótidos no incorporados utilizando sílice-membrana basada columnas giratorias y un robot de procesamiento spin columna dedicada (las columnas de giro también se pueden procesar de forma manual). Siga las instrucciones del fabricante. <ol><li> Transferir el contenido de cada pocillo a un tubo de 2 ml; pre-etiqueta de estos con las identificaciones así. NOTA: Este paso se puede realizar manualmente o preferiblemente usando un robot de manejo de líquidos. </li><li> Si se utiliza un robot de procesamiento columna de centrifugación, a continuación, cargar el robot con tubos de 2 ml, spin columnas de purificación de ADN y tampones asociados. </li><li> Añadir 250 l de sal alta, el ADN de tampón de unión (tampón PB) para la reacción de marcaje para unir el ADN marcado a la sílicemembrana. </li><li> Eliminar las impurezas por lavado de la membrana dos veces con 500 l de tampón de lavado (tampón PE). </li><li> Añadir 15 l de tampón de elución de baja sal (tampón EB) a la membrana para recuperar el, ADN marcado purificado en un volumen de ~ 12 l. </li></ol></li></ol> 3. Combine Pairs Hyb <ol><li> Combine los pares apropiados de cianina 3 y 5 de ADN marcado, COT-1 DNA, una mezcla de bloqueo suministrado por el fabricante y un tampón de hibridación suministrado por el fabricante con un robot de manejo de líquidos. NOTA: Estos pares Hyb pueden ser una muestra y una referencia o muestra vs muestra si CNVs compartido no son un problema (por ejemplo, emparejamos rutinariamente muestras-fenotipo no coincidentes, como un paciente displasia renal vs un paciente craneosinostosis, ya que son muy poco probable que llevar la misma clínicamente significativa CNV). Si se utiliza un ADN de referencia, se recomienda un suministro de ADN comercial, y debe ser procesado junto con la muestra. <ol><li> El uso de un tratamiento de líquidos robot, añadir COT-1 DNA (3333 ng / l), el suministrado por el fabricante de la mezcla y el bloqueo de tampón de hibridación a cada pocillo de una placa de 96 pocillos de manera que cada pocillo contiene 1,1 l COT-1 DNA, 4,95 l de la mezcla de bloqueo y 24,75 tampón de hibridación l. </li><li> Añadir 9,35 l de la DNA de cianina apropiado marcado con 3 a cada pocillo. Pre-húmedo cada punta para mejorar la precisión de pipeteo. </li><li> Añadir 9,35 l de la DNA de cianina apropiado marcado con 5 a cada pocillo. Pre-húmedo cada punta para mejorar la precisión de pipeteo. </li><li> Sellar la placa de 96 pocillos y agitar durante 1 min. Girar la placa de 96 pocillos para recoger contenidos en la parte inferior de cada pocillo. </li></ol></li></ol> 4. La hibridación <ol><li> Precaliente un horno de hibridación a 65 ° C y precalentar una diapositiva de respaldo y una cámara de hibridación para cada diapositiva matriz. <ol><li> Desnaturalizar el ADN marcado en una incubación de pre-hibridación antes de ser aplicable a los arrays. Realizar la hibridación en un horno giratorio durante 24 horas. </li><li> Incubar la placa de 96 pocillos a 70 ° C durante 30 min y luego salir a 37 ° C durante al menos 5 min. </li><li> Trabajando en una plataforma se calentó a 42 ° C, cargar copias de cada diapositiva en una cámara de hibridación antes de su uso. Asegúrese de que la parte transparente de la diapositiva junta se alinea con la parte &#39;con ventanas&#39; de la cámara de hibridación. </li><li> Pipetear 42 l de la mezcla de hibridación preparado previamente (ver sección 3) en la posición adecuada en la matriz de diapositivas respaldo. Pre-húmedo cada punta para mejorar la precisión de pipeteo. Pipeta lentamente hacia el centro de cada posición, asegurándose de que el líquido no toca el límite del anillo de goma. </li><li> Una vez que todas las posiciones de la diapositiva respaldo están llenos, cuidadosamente baje la diapositiva matriz en él y montar la cámara de hibridación. Asegúrese de que el lado de la matriz con la escritura en él se enfrenta a la diapositiva respaldo. Asegúrese de apretar el tornillo de cámara de hibridación totalmente. </li><li> Inspeccione la cámara de hibridación montado. Esegurar que no hay fugas de mezcla de hibridación fuera de los límites de los anillos de goma y cada burbuja de aire es de ~ 4 mm de altura cuando la cámara de hibridación se apoya en su extremo verticalmente. Gire la cámara de hibridación y compruebe que no haya burbujas de aire que están atascados en posición y no se mueve. Si hay alguno de estos, dar la cámara de un golpe seco en el banquillo. Compruebe que todas las burbujas de aire se mueven. </li><li> Coloque la cámara de hibridación en el horno giratorio a 65 ° C durante 24 hr. Asegúrese de que el rotor del horno está equilibrado; utilizar otras cámaras vacías si es necesario. </li></ol></li></ol> 5. Lavado y Escaneo de diapositivas <ol><li> Lávese las matrices para eliminar ADN marcado exceso y luego escanear para medir la fluorescencia de cada sonda. <ol><li> Tome cámaras de hibridación fuera del horno y desmontar. Las diapositivas de la matriz y de la junta serán pegadas; sumergir estos en tampón de lavado 1 y utilizar un par de pinzas, de plástico plana filo para separarlas. </li><li> Discard la diapositiva junta y colocar la placa matriz en un rack sumergido en tampón 1. </li><li> Lavar el portaobjetos matriz en ~ 700 ml de tampón de lavado fresca 1 durante 5 min, se agita vigorosamente (utilizar una pulga y un agitador magnético). </li><li> Transferir el portaobjetos matriz a ~ 700 ml de tampón de lavado 2 y lavar durante 90 segundos, revolviendo vigorosamente. Levante suavemente las diapositivas de matriz fuera de tampón de lavado 2, deben surgir seco. </li><li> Cargar la diapositiva matriz en un soporte de diapositivas del escáner, utilizando un protector de diapositivas. Cargue la diapositiva en el escáner matriz y escanear siguiendo las instrucciones del fabricante matriz. </li></ol></li></ol>

<ol>
	<li>Miller, D. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Consensus+statement:+chromosomal+microarray+is+a+first-tier+clinical+diagnostic+test+for+individuals+with+developmental+disabilities+or+congenital+anomalies.">Consensus statement: chromosomal microarray is a first-tier clinical diagnostic test for individuals with developmental disabilities or congenital anomalies.</a> Am. J. Hum. Genet. 86, 749-764 (2010).</li><li>Ahn, J. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Array+CGH+as+a+first+line+diagnostic+test+in+place+of+karyotyping+for+postnatal+referrals+-+results+from+four+years'+clinical+application+for+over+8,700+patients.">Array CGH as a first line diagnostic test in place of karyotyping for postnatal referrals - results from four years' clinical application for over 8,700 patients.</a> Mol. Cytogenet. 6 (16), 1755-8166 (2013).</li><li>Ahn, J. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+and+implementation+of+array+comparative+genomic+hybridisation+as+a+first+line+test+in+place+of+postnatal+karyotyping+for+genome+imbalance.">Validation and implementation of array comparative genomic hybridisation as a first line test in place of postnatal karyotyping for genome imbalance.</a> Mol. Cytogenet. 3 (9), 1755-8166 (2010).</li><li>Beaudet, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+utility+of+chromosomal+microarray+analysis+in+developmental+and+behavioral+pediatrics.">The utility of chromosomal microarray analysis in developmental and behavioral pediatrics.</a> Child Dev. 84, 121-132 (2013).</li><li>Park, S. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+implementation+of+whole-genome+array+CGH+as+a+first-tier+test+in+5080+pre+and+postnatal+cases.">Clinical implementation of whole-genome array CGH as a first-tier test in 5080 pre and postnatal cases.</a> Mol. Cytogenet. 4, 12 (2011).</li><li>Iafrate, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+large-scale+variation+in+the+human+genome.">Detection of large-scale variation in the human genome.</a> Nat. Genet. 36, 949-951 (2004).</li><li>Redon, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Global+variation+in+copy+number+in+the+human+genome.">Global variation in copy number in the human genome.</a> Nature. 444, 444-454 (2006).</li><li>Cafferkey, M., Ahn, J. W., Flinter, F., Ogilvie, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phenotypic+features+in+patients+with+15q11.2(BP1-BP2)+deletion:+Further+delineation+of+an+emerging+syndrome.">Phenotypic features in patients with 15q11.2(BP1-BP2) deletion: Further delineation of an emerging syndrome.</a> Am. J. Med. Genet. A. 164, 1916-1922 (2014).</li><li>Molin, A. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+microdeletion+syndrome+at+3q13.31+characterised+by+developmental+delay,+postnatal+overgrowth,+hypoplastic+male+genitals,+and+characteristic+facial+features.">A novel microdeletion syndrome at 3q13.31 characterised by developmental delay, postnatal overgrowth, hypoplastic male genitals, and characteristic facial features.</a> J. Med. Genet. 49, 104-109 (2012).</li><li>Tropeano, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Male-biased+autosomal+effect+of+16p13.11+copy+number+variation+in+neurodevelopmental+disorders.">Male-biased autosomal effect of 16p13.11 copy number variation in neurodevelopmental disorders.</a> PLoS One. 8, e61365 (2013).</li><li>Bon, B. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Further+delineation+of+the+15q13+microdeletion+and+duplication+syndromes:+a+clinical+spectrum+varying+from+non-pathogenic+to+a+severe+outcome.">Further delineation of the 15q13 microdeletion and duplication syndromes: a clinical spectrum varying from non-pathogenic to a severe outcome.</a> J. Med. Genet. 46, 511-523 (2009).</li></ol>

The authors have nothing to disclose.

Array CGH no detectará reordenamientos balanceados o anormalidades ploidía como triploidía. Además, los desequilibrios de mosaico de bajo nivel no se pueden detectar. Sin embargo, array CGH tiene una mayor resolución para la detección de la CNV de análisis cromosómico bandas-G del cual ha sustituido en muchos laboratorios de citogenética. Por lo tanto, es el actual estándar de oro para la detección de la CNV en todo el genoma. Puede ser reemplazado por las tecnologías de secuenciación de próxima generació...

Se ha sabido durante muchos años que las supresiones o copias extra de segmentos cromosómicos provocan discapacidad intelectual, dismorfia y malformaciones congentical, y en algunos casos causar síndromes genéticos 1. Sin embargo, la única tecnología disponible hasta mediados de la década de 2000 para la detección de todo el genoma de estos cambios fue G-bandas cromosoma análisis, que tiene una resolución de alrededor de 5-10 MB, dependiendo de la región y la naturaleza de los desequilibrios, y que no puede detectar cromosomas anormales donde el material ha sido reemplazado por una región de un cromosoma diferente con el mismo patrón de bandas. Técnicas citogenéticas auxiliares tales como la hibridación fluorescente in situ y la sonda de amplificación ligadura específica multiplex han estado disponibles durante el interrogatorio de loci específicos, en los casos de sospecha de desequilibrio sindrómico específico, pero no fue hasta la introducción de la gama de hibridación genómica comparada (CGH array) en s de diagnóstico clínico de rutinaervicio 2-5 que la detección de todo el genoma de las variantes de número de copias (CNV) se hizo posible en un gran aumento de resolución (por lo general alrededor de 120kb). Trabajos de servicio clínico junto estudios de investigación han demostrado que la CNV para algunas regiones se han generalizado en la población normal 6-7, mientras que otro CNV, previamente indetectables, están asociados con neurodisabilities como el autismo y la epilepsia 8-11. El protocolo descrito en este documento se utiliza en nuestro laboratorio de diagnóstico clínico UK National Health Service (NHS); utilizamos estrategias de hibridación novela, ensayo de lotes y la robótica para minimizar el costo de este servicio financiado por el estado. Antes de el protocolo detallado a continuación, el ADN de alta calidad debe ser extraído del material de partida apropiado, comúnmente sangre, células cultivadas o muestras de tejido. Espectrofotometría se puede utilizar para medir la concentración (debe ser&gt; 50 ng / ul) y comprobar 260: 280 razón de absorbancia (b debee 1,8-2,0). La electroforesis en gel se puede utilizar para verificar que el ADN es de alto peso molecular sin degradación significativa. Este protocolo está diseñado para los laboratorios de mayor rendimiento que está etiquetando 96 muestras por corrida utilizando la robótica de manipulación de líquidos automatizados. Sin embargo, puede ser adaptado para laboratorios de rendimiento inferiores sin automatización.

<table><tbody><tr><td>CGH microarray 8 x 60K</td><td>Agilent</td><td>G4126</td><td></td></tr><tr><td>Array CGH wash buffers</td><td>Agilent</td><td>5188-5226</td><td></td></tr><tr><td>Array CGH hybridisation buffer</td><td>Agilent</td><td>5188-5380</td><td></td></tr><tr><td>Minelute purification kit</td><td>Qiagen</td><td>28006</td><td></td></tr><tr><td>Array CGH labelling kit</td><td>Enzo</td><td>ENZ-42672-0000</td><td></td></tr></tbody></table>

array comparative genomic hybridization (array cgh) for detection of genomic copy number variants

Array CGH for the detection of genomic copy number variants has replaced G-banded karyotype analysis. This paper describes the technology and its application in a clinical diagnostic service laboratory. DNA extracted from a patient&#8217;s sample (blood, saliva or other tissue types) is labeled with a fluorochrome (either cyanine 5 or cyanine 3). A reference DNA sample is labeled with the opposite fluorochrome. There follows a cleanup step to remove unincorporated nucleotides before the labeled DNAs are mixed and resuspended in a hybridization buffer and applied to an array comprising ~60,000 oligonucleotide probes from loci across the genome, with high probe density in clinically important areas. Following hybridization, the arrays are washed, then scanned and the resulting images are analyzed to measure the red and green fluorescence for each probe. Software is used to assess the quality of each probe measurement, calculate the ratio of red to green fluorescence and detect potential copy number variants.

Cada sonda en una matriz hibridada se visualiza como una mezcla de fluorocromos rojo y verde (véase la Figura 1). La proporción de rojo a la señal fluorescente verde para cada sonda se cuantifica por el escáner y el software asociado traza en log2 ratios de acuerdo a su posición genómica, e identifica las regiones incluidas límites preestablecidos fuera. Las huellas de la matriz resultantes permiten la interpretación de las regiones identificadas como genómicamente desequilibrada. Por ejemplo, ...

Watch this Scientific Journal Video about Array Comparative Genomic Hybridization Array CGH for Detection of Genomic Copy Number Variants at JoVE.com

Array Comparative Genomic Hybridization Array CGH for Detection of Genomic Copy Number Variants

CGH array para la detección de variantes de número de copias genómicas ha reemplazado análisis de cariotipo de bandas-G. Este artículo describe la tecnología y su aplicación en un laboratorio de servicio de diagnóstico.

Matriz de hibridación genómica comparada (CGH array) para la detección de número de copias genómicas variantes

Array CGH for the detection of genomic copy number variants has replaced G-banded karyotype analysis. This paper describes the technology and its ...

array-comparative-genomic-hybridization-array-cgh-for-detection

Research

JoVE Journal

Biology

Array Comparative Genomic Hybridization (Array CGH) for Detection of Genomic Copy Number Variants

19.5K vistas.  Guy's & St Thomas' NHS Foundation Trust.  CGH array para la detección de variantes de número de copias genómicas ha reemplazado análisis de cariotipo de bandas-G. Este artículo describe la tecnología y su aplicación en un laboratorio de servicio de diagnóstico. 

Video: Array Comparative Genomic Hybridization Array CGH for Detection of Genomic Copy Number Variants

Detection of Copy Number Alterations Using Single Cell Sequencing

Detection of genomic changes at single cell resolution is important for characterizing genetic heterogeneity and evolution in normal tissues, cancers, and microbial populations. Traditional methods for assessing genetic heterogeneity have been limited by low resolution, low sensitivity, and/or low specificity. Single cell sequencing has emerged as a powerful tool for detecting genetic heterogeneity with high resolution, high sensitivity and, when appropriately analyzed, high specificity. Here we provide a protocol for the isolation, whole genome amplification, sequencing, and analysis of single cells. Our approach allows for the reliable identification of megabase-scale copy number variants in single cells. However, aspects of this protocol can also be applied to investigate other types of genetic alterations in single cells.

Single cell sequencing is an increasingly popular and accessible tool for addressing genomic changes at high resolution. We provide a protocol that uses single cell sequencing to identify copy number alterations in single cells.

Detección del número de copias alteraciones Uso de Secuenciación de los organismos unicelulares

Detection of genomic changes at single cell resolution is important for characterizing genetic heterogeneity and evolution in normal tissues, cancers, and ...

Investigación

Genética

FISH for Pre-implantation Genetic Diagnosis 

Pre-implantation genetic diagnosis (PGD) is an established alternative to pre-natal diagnosis, and involves selecting pre-implantation embryos from a cohort generated by assisted reproduction technology (ART). This selection may be required because of familial monogenic disease (e.g. cystic fibrosis), or because one partner carries a chromosome rearrangement (e.g. a two-way reciprocal translocation). PGD is available for couples who have had previous affected children, and/or in the case of chromosome rearrangements, recurrent miscarriages, or infertility. Oocytes aspirated following ovarian stimulation are fertilized by in vitro immersion in semen (IVF) or by intracytoplasmic injection of an individual spermatozoon (ICSI). Pre-implantation cleavage-stage embryos are biopsied, usually by the removal of a single cell on day 3 post-fertilization, and the biopsied cell is tested to establish the genetic status of the embryo. Fluorescence in situ hybridization (FISH) on the fixed nuclei of biopsied cells with target-specific DNA probes is the technique of choice to detect chromosome imbalance associated with chromosome rearrangements, and to select female embryos in families with X-linked disease for which there is no mutation-specific test. FISH has also been used to screen embryos for spontaneous chromosome aneuploidy (also known as PGS or PGD-AS) in order to try and improve the efficiency of assisted reproduction; however, the predictive value of this test using the spreading and FISH technique described here is likely to be unacceptably low in most people's hands and it is not recommended for routine clinical use. We describe the selection of suitable probes for single-cell FISH, spreading techniques for blastomere nuclei, and in situ hybridization and signal scoring, applied to PGD in a clinical setting.

FISH for Pre-implantation Genetic Diagnosis

This article describes the selection of suitable probes for single-cell FISH, spreading techniques for blastomere nuclei, and in situ hybridization and signal scoring, applied to pre-implantation genetic diagnosis (PGD) in a clinical setting.

FISH para el diagnóstico genético preimplantacional

Pre-implantation genetic diagnosis (PGD) is an established alternative to pre-natal diagnosis, and involves selecting pre-implantation embryos from a ...

Medicina

Serum and Plasma Copy Number Detection Using Real-time PCR

Serum and plasma cell free DNA (cfDNA) has been shown as an informative, non-invasive source of biomarkers for cancer diagnosis, prognosis, monitoring, and prediction of treatment resistance. Starting from the hypothesis that androgen receptor (AR) gene copy number (CN) gain is a frequent event in metastatic castration resistance prostate cancer (mCRPC), we propose to analyze this event in cfDNA as a potential predictive biomarker.
We evaluated AR CN in cfDNA using 2 different real-time PCR assays and 2 reference genes (RNaseP and AGO1). DNA amount of 60 ng was used for each assay combination. AR CN gain was confirmed using Digital PCR as a more accurate method. CN variation analysis has already been demonstrated to be informative for the prediction of treatment resistance in the setting of mCRPC, but it could be useful also for other purposes in different patient settings. CN analysis on cfDNA has several advantages: it is non-invasive, rapid and easy to perform, and it starts from a small volume of serum or plasma material.

This manuscript describes the copy number variation analysis performed in serum or plasma DNA using real-time PCR approach. This method is suitable for the prediction of drug resistance in castration resistant prostate cancer patients, but it could be informative also for other diseases.

Suero y Plasma copia número detección mediante PCR en tiempo real

Serum and plasma cell free DNA (cfDNA) has been shown as an informative, non-invasive source of biomarkers for cancer diagnosis, prognosis, monitoring, ...

Investigación sobre el cáncer

An Array-based Comparative Genomic Hybridization Platform for Efficient Detection of Copy Number Variations in Fast Neutron-induced Medicago truncatula Mutants

Mutants are invaluable genetic resources for gene function studies. To generate mutant collections, three types of mutagens can be utilized, including biological such as T-DNA or transposon, chemical such as ethyl methanesulfonate (EMS), or physical such as ionization radiation. The type of mutation observed varies depending on the mutagen used. For ionization radiation induced mutants, mutations include deletion, duplication, or rearrangement. While T-DNA or transposon-based mutagenesis is limited to species that are susceptible to transformation, chemical or physical mutagenesis can be applied to a broad range of species. However, the characterization of mutations derived from chemical or physical mutagenesis traditionally relies on a map-based cloning approach, which is labor intensive and time consuming. Here, we show that a high-density genome array-based comparative genomic hybridization (aCGH) platform can be applied to efficiently detect and characterize copy number variations (CNVs) in mutants derived from fast neutron bombardment (FNB) mutagenesis in Medicago truncatula, a legume species. Whole genome sequence analysis shows that there are more than 50,000 genes or gene models in M. truncatula. At present, FNB-induced mutants in M. truncatula are derived from more than 150,000 M1 lines, representing invaluable genetic resources for functional studies of genes in the genome. The aCGH platform described here is an efficient tool for characterizing FNB-induced mutants in M. truncatula.

An Array-based Comparative Genomic Hybridization Platform for Efficient Detection of Copy Number Variations in Fast Neutron-induced Medicago truncatula Mutants

This protocol provides experimental steps and information about reagents, equipment, and analysis tools for researchers who are interested in carrying out whole genome array-based comparative genomic hybridization (CGH) analysis of copy number variations in plants.

Una basada en arreglos comparativo genómica hibridación plataforma eficiente detección de copia número de las variaciones en mutantes rápido neutrón-inducida de Medicago truncatula

Mutants are invaluable genetic resources for gene function studies. To generate mutant collections, three types of mutagens can be utilized, including ...

Detection of a CDH1 Rare Transcript Variant in Fresh-frozen Gastric Cancer Tissues by Chip-based Digital PCR

CDH1a, a non-canonical transcript of the CDH1 gene, has been found to be expressed in some gastric cancer (GC) cell lines, whereas it is absent in normal gastric mucosa. Recently, we detected CDH1a transcript variant in fresh-frozen tumor tissues obtained from patients with GC. The expression of this variant in tissue samples was investigated by the chip-based digital PCR (dPCR) approach presented here. dPCR offers the potential for an accurate, robust, and highly sensitive measurement of nucleic acids and is increasingly utilized for many applications in different fields. dPCR is capable of detecting rare targets; in addition, dPCR offers the possibility for absolute and precise quantification of nucleic acids without the need for calibrators and standard curves. In fact, the reaction partitioning enriches the target from the background, which improves amplification efficiency and tolerance to inhibitors. Such characteristics make dPCR an optimal tool for the detection of the CDH1a rare transcript.

Detection of a CDH1 Rare Transcript Variant in Fresh-frozen Gastric Cancer Tissues by Chip-based Digital PCR

The manuscript describes a chip-based digital PCR assay to detect a rare CDH1 transcript variant (CDH1a) in fresh-frozen normal and tumor tissues obtained from patients with gastric cancer.

Detección de una variante rara transcripción de CDH1 en tejidos de cáncer gástrico congelado por PCR Digital basado en el Chip

CDH1a, a non-canonical transcript of the CDH1 gene, has been found to be expressed in some gastric cancer (GC) cell lines, whereas it is absent in normal ...

Candidate Gene Testing in Clinical Cohort Studies with Multiplexed Genotyping and Mass Spectrometry

Complex diseases are often underpinned by multiple common genetic variants that contribute to disease susceptibility. Here, we describe a cost-effective tag single nucleotide polymorphism (SNP) approach using a multiplexed genotyping assay with mass spectrometry, to investigate gene pathway associations in clinical cohorts. We investigate the food allergy candidate locus Interleukin13 (IL13) as an example. This method efficiently maximizes the coverage by taking advantage of shared linkage disequilibrium (LD) within a region. Selected LD SNPs are then designed into a multiplexed assay, enabling up to 40 different SNPs to be analyzed simultaneously, boosting cost-effectiveness. Polymerase chain reaction (PCR) is used to amplify the target loci, followed by single nucleotide extension, and the amplicons are then measured using matrix-assisted laser desorption/ionization-time of flight(MALDI-TOF) mass spectrometry. The raw output is analyzed with the genotype calling software, using stringent quality control definitions and cut-offs, and high probability genotypes are determined and output for data analysis.

Identification of genetic variants contributing to complex human disease allows us to identify novel mechanisms. Here, we demonstrate a multiplex genotyping approach to candidate genes or gene pathway analysis that maximizes the coverage at low cost and is amenable to cohort-based studies.

Genes candidatos en estudios de cohorte clínica con genotipificación multiplexado y espectrometría de masas

Complex diseases are often underpinned by multiple common genetic variants that contribute to disease susceptibility. Here, we describe a cost-effective ...

Technical Demonstration of Whole Genome Array Comparative Genomic Hybridization

Array comparative genomic hybridization (array CGH) is a method for detecting gains and losses of DNA segments or gene dosage in the genome 1. Recent advances in this technology have enabled high resolution comparison of whole genomes for the identification of genetic alterations in cancer and other genetic diseases 2. The Sub-Megabase Resolution Tiling-set array (or SMRT) array is comprised of a set of approximately thirty thousand overlapping bacterial artificial chromosome (BAC) clones that span the human genome in ~100 kilobase pair (kb) segments 2. These BAC targets are individually synthesized and spotted in duplicate on a single glass slide 2-4. Array CGH is based on the principle of competitive hybridization. Sample and reference DNA are differentially labeled with Cyanine-3 and Cyanine-5 fluorescent dyes, and co-hybridized to the array. After an incubation period the unbound samples are washed from the slide and the array is imaged. A freely available custom software package called SeeGH (www.flintbox.ca) is used to process the large volume of data collected - a single experiment generates 53,892 data points. SeeGH visualizes the log2 signal intensity ratio between the 2 samples at each BAC target which is vertically aligned with chromosomal position 5,6. The SMRT array can detect alterations as small as 50 kb in size 7. The SMRT array can detect a variety of DNA rearrangement events including DNA gains, losses, amplifications and homozygous deletions. A unique advantage of the SMRT array is that one can use DNA isolated from formalin fixed paraffin embedded samples. When combined with the low input requirements of unamplified DNA (25-100ng) this allows profiling of precious samples such as those produced by microdissection 7,8. This is attributed to the large size of each BAC hybridization target that allows the binding of sufficient labeled samples to produce signals for detection. Another advantage of this platform is the tolerance of tissue heterogeneity, decreasing the need for tedious tissue microdissection 8. This video protocol is a step-by-step tutorial from labeling the input DNA through to signal acquisition for the whole genome tiling path SMRT array.

This video is a technical demonstration of the hybridization protocol for whole genome tiling path array CGH, which scans the entire human genome using only 25-100 ng of DNA that can be isolated from a variety of sources, including archival formalin fixed material.

Demostración de técnicas de hibridación del genoma entero matriz Genómica Comparativa

Array comparative genomic hybridization (array CGH) is a method for detecting gains and losses of DNA segments or gene dosage in the genome 1.  Recent ...

Biología

Pre-Implantation Genetic Testing for Aneuploidy on a Semiconductor Based Next-Generation Sequencing Platform

Next-generation sequencing has gained increasing importance in the clinical application in the determination of genetic variants. In the pre-implantation genetic test, this technique has its unique advantages in scalability, throughput, and cost. For the pre-implantation genetic test for aneuploidy analysis, the semiconductor-based next-generation sequencing (NGS) system presented here provides a comprehensive approach to determine structural genetic variants at a minimum resolution of 8 Mb. From sample acquisition to the final report, the working process requires multiple steps with close adherence to protocols. Since various critical steps could determine the outcome of amplification, quality of the library, coverage of reads, and output of data, descriptive information with visual demonstration other than words could offer more detail to the operation and manipulation, which may have a great impact on the results of all critical steps. The methods presented herein will display the procedures involved in whole genome amplification (WGA) of biopsied Trophectoderm (TE) cells, genomic library construction, sequencer management, and finally, generating copy number variants' reports.

The protocol presents the overall in-lab procedures required in pre-implantation genetic testing for aneuploidy on a semiconductor-based next-generation sequencing platform. Here we present the detailed steps of whole genome amplification, DNA fragment selection, library construction, template preparation, and sequencing working flow with representative results.

Pruebas genéticas preimplantacionales para aneuploidías en una plataforma de secuenciación de próxima generación basada en semiconductores

Next-generation sequencing has gained increasing importance in the clinical application in the determination of genetic variants. In the pre-implantation ...

Comparative Lesions Analysis Through a Targeted Sequencing Approach

Assessing intra-tumoral heterogeneity (ITH) is of paramount importance to anticipate failure of targeted therapies and design accordingly effective anti-tumor strategies. Although concerns are frequently raised due to differences in sample processing and depth of coverage, next-generation sequencing of solid tumors have unraveled a highly variable degree of ITH across tumor types. Capturing the genetic relatedness between primary and metastatic lesions through the identification of clonal and subclonal populations is critical to the design of therapies for advance-stage diseases. Here, we report a method for comparative lesions analysis that allows for the identification of clonal and subclonal populations among different specimens from the same patient. The experimental approach described here integrates three well-established approaches: histological analysis, high-coverage multi-lesion sequencing, and immunophenotypic analyses. In order to minimize the effects on the detection of subclonal events by inappropriate sample processing, we subjected tissues to careful pathological examination and neoplastic cell enrichment. Quality controlled DNA from neoplastic lesions and normal tissues was then subjected to high coverage sequencing, targeting the coding regions of 409 relevant cancer genes. While only looking at a limited genomic space, our approach enables evaluating the extent of heterogeneity among somatic alterations (single-nucleotide mutations and copy-number variations) in distinct lesions from a given patient. Through comparative analysis of sequencing data, we were able to distinguish clonal vs. subclonal alterations. The majority of ITH is often ascribed to passenger mutations; therefore, we also used immunohistochemistry to predict functional consequences of mutations. While this protocol has been applied to a specific tumor type, we anticipate that the methodology described here is broadly applicable to other solid tumor types.

This article describes a method to identify clonal and subclonal alterations among different specimens from a given patient. Although the experiments described here focus on a specific tumor type, the approach is broadly applicable to other solid tumors.

Análisis comparativo de lesiones a través de un enfoque de secuenciación dirigida

Assessing intra-tumoral heterogeneity (ITH) is of paramount importance to anticipate failure of targeted therapies and design accordingly effective ...

Comportamiento

Simple Bulk Readout of Digital Nucleic Acid Quantification Assays

Digital assays are powerful methods that enable detection of rare cells and counting of individual nucleic acid molecules. However, digital assays are still not routinely applied, due to the cost and specific equipment associated with commercially available methods. Here we present a simplified method for readout of digital droplet assays using a conventional real-time PCR instrument to measure bulk fluorescence of droplet-based digital assays.
We characterize the performance of the bulk readout assay using synthetic droplet mixtures and a droplet digital multiple displacement amplification (MDA) assay. Quantitative MDA particularly benefits from a digital reaction format, but our new method&#160;applies to any digital assay. For established digital assay protocols such as digital PCR, this method serves to speed up and simplify assay readout.
Our bulk readout methodology brings the advantages of partitioned assays without the need for specialized readout instrumentation. The principal limitations of the bulk readout methodology are reduced dynamic range compared with droplet-counting platforms and the need for a standard sample, although the requirements for this standard are less demanding than for a conventional real-time experiment. Quantitative whole genome amplification (WGA) is used to test for contaminants in WGA reactions and is the most sensitive way to detect the presence of DNA fragments with unknown sequences, giving the method great promise in diverse application areas including pharmaceutical quality control and astrobiology.

We describe an endpoint digital assay for quantifying nucleic acids with a simplified (analog) readout. We measure bulk fluorescence of droplet-based digital assays using a standard qPCR machine rather than specialized instrumentation and confirm our results by microscopy.

Lectura granel simple de Digital ácidos nucleicos Cuantificación ensayos

Digital assays are powerful methods that enable detection of rare cells and counting of individual nucleic acid molecules. However, digital assays are ...