【原】阵列比较基因组/杂交基因组分析技术

Comparative genomic hybridization (CGH) or Chromosomal Microarray Analysis (CMA)

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|核心内容：

阵列比较基因组/杂交基因组分析技术是一项新技术，它比传统的细胞遗传学技术能够对整个基因组进行更为详细的分析。

传统的细胞遗传学可以检测大于5Mb 的 DNA 数量变化。利用分子遗传学技术，我们可以检测到 DNA 序列中一个碱基对的变化，但是必须提前确定目标区域或基因才能做到这一点。

微阵列结合了传统分子和细胞遗传学的特点，可以进行整个基因组筛选，但能够检测小于5Mb 的变化。这允许检测微重复和/或微删除的精确边界。反过来，这些片段中的特定基因可以被识别，这可能具有临床意义。

用荧光染料标记样本和对照样本的 DNA，然后与寡核苷酸杂交。结果分析使用定量成像方法和分析软件，以协助确定每个目标 DNA 序列丢失的拷贝数，增加的拷贝数，或正常拷贝数。

该技术已在已知微缺失/重复和其他传统细胞遗传学方法检测的不平衡核型患者中得到验证。

CMA 不会检测到低水平的镶嵌、平衡易位或反转。

任何具有畸形特征、不明原因的智力迟钝/发育迟缓、非遗传综合征特有的先天性异常、癫痫、语言迟缓、多次流产、肿瘤分析以帮助诊断以及任何具有正常染色体分析的患者，都可以获得 CMA。 

方法: 阵列比较基因组杂交分析400k探针 

目的: 临床诊断、科学研究

一个典型的用于最常见的染色体异常的阵列CGH分析步骤

这个图显示了 BAC 数组计算全息图的步骤。(1)从基因组物理图谱中选择 BAC 克隆。(2)从选定的 BAC 克隆中提取 DNA 样本，并通过 DNA 指纹或序列分析分析进行鉴定。(3)多步放大过程从每个克隆产生足够的材料用于阵列定位。每个克隆都被复制到一个坚固的支撑体上。(4)用花青3和花青5差异标记参考 DNA 和试验 DNA。(5)将两种标记产物组合并杂化到带斑点的载玻片上。(6)通过两通道扫描获得杂化载玻片的图像。来自单个斑点的信号强度比可以显示为一个简单的图(7)或使用更复杂的软件，如 SeeGH，它可以显示整个基因组的拷贝数改变(8)

原文：

Comparative genomic hybridization (CGH) or Chromosomal Microarray Analysis (CMA) is a recent technology development that allows for an entire genome to be analyzed in more detail than is possible using conventional cytogenetics. Conventional Cytogenetics can detect changes in the amount of DNA >5Mb. Convential Molecular genetic techniques allow us to detect changes of as little as one base pair of the DNA sequence, however the target area or gene has to be identified in advance to make this possible. Microarrays combine the assets of both conventional molecular and cytogenetics to allow a whole genome screen to be performed but with the ability to detect changes smaller than 5Mb. This allows for the exact boundaries of microduplications and/or microdeletions to be detected. In turn, the specific genes in these segments can be identified, which may be of clinical significance. DNA from the test sample and a control sample are labeled with fluorescent dyes and hybridized to the oligos. Results are analyzed using quantitative imaging methods and analytical software is used to assist in identifying each targeted-DNA sequence as loss of copy number, gain of copy number, or normal copy number. This technology has been validated on patients with known microdeletions/duplications and other unbalanced karyotypes detected by traditional cytogenetic methods. CMA will not detect low level mosaicism, balanced translocations, or inversions. CMA may be ordered for anyone with dysmorphic features, unexplained mental retardation/developmental delay, congenital anomalies not specific to a genetic syndrome, seizures, speech delay, multiple miscarriages, tumor analysis to aid in diagnosis, and any patient with normal chromosome analysis. Methodology: Comparative Genomic Hybridization analysis 400k probes Purpose: Confirmation of Clinical Diagnosis.

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参考文献：https://embryology.med./embryology/index.php?title=File:Steps_in_a_classic_array_CGH-analysis_used_for_the_most_common_chromosomal_abnormalities.png

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