揭秘二代测序：从样本到数据的建库全流程解析

引言

二代测序（Second-Generation Sequencing，简称SGS）技术自2005年问世以来，以其高通量、低成本、高灵敏度等特点，迅速成为生命科学领域的研究热点。本文将详细解析二代测序从样本处理到数据建库的全流程，帮助读者全面了解这一技术。

样本准备

1. 样本类型

二代测序的样本类型多样，包括DNA、RNA、蛋白质等。其中，DNA测序应用最为广泛，如基因组测序、转录组测序等。

2. 样本提取

2.1 DNA提取

DNA提取方法包括酚-氯仿法、柱式提取法等。以下以酚-氯仿法为例：

# 酚-氯仿法DNA提取
1. 将样本加入等体积的酚-氯仿溶液，混匀。
2. 12,000 rpm离心10分钟，取上清液。
3. 加入等体积的氯仿，混匀。
4. 12,000 rpm离心10分钟，取上清液。
5. 加入等体积的75%乙醇，混匀。
6. 7,500 rpm离心5分钟，弃上清液。
7. 将沉淀用75%乙醇洗涤。
8. 室温干燥后，用适量TE缓冲液溶解。

2.2 RNA提取

RNA提取方法与DNA提取类似，但需注意RNA易降解，操作需在低温条件下进行。

建库

1. 建库策略

二代测序建库策略主要有以下几种：

• Illumina/Solexa平台：基于合成测序技术，包括PCR扩增、连接接头、构建文库等步骤。
• Illumina HiSeq平台：采用双末端测序技术，可同时获得序列的5’和3’端信息。
• Illumina MiSeq平台：采用单末端测序技术，具有更高的测序通量和更低的成本。

2. 建库步骤

以下以Illumina/Solexa平台为例，介绍建库步骤：

2.1 PCR扩增

1. 将提取的DNA进行PCR扩增，获得足够长度的DNA片段。
2. 使用特异性引物，将DNA片段连接到测序接头。

2.2 连接接头

1. 将连接接头的DNA片段进行纯化，去除未连接的接头。
2. 将纯化后的DNA片段进行PCR扩增，获得具有接头的DNA片段。

2.3 构建文库

1. 将扩增后的DNA片段进行纯化，去除未连接的接头。
2. 将纯化后的DNA片段进行PCR扩增，获得具有接头的DNA片段。
3. 将扩增后的DNA片段进行文库构建，包括连接、纯化等步骤。

测序

1. 测序平台

二代测序平台主要有以下几种：

• Illumina HiSeq
• Illumina MiSeq
• Illumina NextSeq
• Illumina HiSeq X
• Illumina HiSeq 4000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
• Illumina HiSeq 2000
• Illumina HiSeq 2500
• Illumina HiSeq 3000
• Illumina HiSeq 4000
• Illumina HiSeq 5000
• Illumina HiSeq 7000
• Illumina HiSeq 1000
• Illumina HiSeq 1500
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