目的：探讨GJB2全序列长链PCR方法和琼脂糖凝胶电泳方法，以及影响长链PCR和电泳结果的可能因素。方法应用Primer Premier 5.0软件和Oligo 6 Demo软件针对GJB2全序列设计引物，应用DNA聚合酶KOD FX Neo试剂盒进行两步法长链PCR扩增，调整加入DNA模板量、PCR延伸时间、循环次数等影响PCR产物量，通过0.8%琼脂糖凝胶电泳检测PCR产物长度和量，调整加样槽的宽度、加样量、电泳电压、电流、电泳时间得到清晰条带，若PCR产物存在大片段碱基插入或缺失，用限制性内切酶BamHI进行内切酶反应，初步判断插入或缺失的大致位置。结果正向引物F：5’-AGATCGGGACCTCGAAGGGGACTTG-3’；反向引物R：5’-AGGTGGGCACGGGGTTAGGTAGAAA-3’，扩增片段长5887 bp。长链PCR条件为：50μl的反应体系中加入2μl（约40 ng）的基因组DNA，预变性94℃2分钟，变性98℃10秒，68℃延伸5分钟，共32个循环。电泳条件为：加样槽5 mm宽，每槽加样0.8μl PCR产物，电泳电压50 V，电流50 mA，电泳时间140分钟。结论应用DNA聚合酶KOD FX Neo试剂盒进行两步法长链PCR，可进行GJB2全序列扩增，影响PCR的可能因素为引物、DNA模板的质和量、延伸时间、循环次数等。0.8%琼脂糖凝胶电泳可获得较好的分离效果，影响电泳可能的因素为加样槽宽度、加样量、电泳电压、电流、电泳时间等。
Hearing loss is one of the most common birth defects,with inherited genetic defects play an important role,contributing to about 60%of deafness occurring in infants.However,hearing impairment is genetically heterogeneous,with both common and rare forms occurring due to mutations in estimated 500 genes.Due to the large number and presumably low mutation frequencies of those genes,it would be highly expensive and time-consuming to address this issue by conventional gene-by-gene Sanger sequencing.Next-generation sequencing is a revolutionary technology that allows the simultaneous screening of mutations in a large number of genes.It is cost effective compared to classical strategies of linkage analysis and direct sequencing when the number or size of genes is large,and thus has become a highly efficient strategy for identifying novel causative genes and mutations involved in heritable disease.In this review, we describe major NGS methodologies currently used for genetic disorders and highlight applications of these technologies in studies of molecular diagnosis and the discovery of genes implicated in non-syndromic hearing loss.
