IDT的xGen®Lockdown®Probes是 5’端带生物素的oligos，且每条探针都是单独合成，用于二代测序目标区域捕获。

利用这些探针可以创建自定义捕获panels，这些panels可以重新被优化，扩展，或者结合其他panels使用。xGen®Lockdown®Probes也可以提高现有捕获panels的捕获效果，针对高G/C含量等复杂区域同样可以得到好的实验结果。

特点：

·该5’生物素标记的探针是我们应用专有的高耦合效率合成方法生产的。

·每条探针都经QC质谱评估。

·每个pool内的探针数量高达2000条，也可以定制具有更多探针的pool。

·xGen Predesigned Gene Capture Pools可用于任何人的RefSeq编码基因。

应用：

创建实惠的针对小目标区域的自定义panels:

·针对感兴趣的目标区域创建特定的sub-panels。

·获得足够的测序覆盖深度检测稀有的等位基因。

·测序大量样本经济成本更低。

·优化，扩展或结合其他panels使用。

锚定入 array-derived baits提高捕获效率:

·填补芯片外显子捕获或更大的捕获中的遗漏区域。

·提高整个目标区域的覆盖均一性。

·发现基因突变可信度更高。

·可选择性的提高感兴趣的目标区域，而不需要重新定制panels。

高目标区域覆盖度

xGen Lockdown Probes可提供约500倍的富集，超过目标区域的高覆盖(Figure 1)，和最低的GC偏向性。

Figure 1. xGen®Lockdown®Probes yield high coverage.Ligation-based sequencing libraries were amplified by PCR using HiFi DNA polymerase (Kapa Biosystems). A set of 1000 xGen Lockdown Probes spanning the targeted region was used for in-solution hybrid selection with 2 µg library input. Hybridization was performed for 24 hr and enriched targets were sequenced on a HiSeq 2000 System (Illumina) using 49 x 49 paired-end reads. The xGen Lockdown Probes provided greater coverage than array/RNA baits.

提高array-synthesized baits

xGen Lockdown Probes可加入到array-derived RNA baits用于提高GC富集目标区域的覆盖度，比如第一个外显子（Figure 2）。

Figure 2. Spiking in individually synthesized oligonucleotide baits improves sequencing coverage of array-derived RNA baits.Individually synthesized 5′-biotinylated Ultramer®Oligonucleotides (xGen®Lockdown®Probes) were spiked into commercial, array-synthesized RNA baits to improve coverage of areas with high GC content. Either (A) 1000 Ultramer oligo baits targeting a ~133 kb region, or (B) 3 Ultramer oligo baits targeting a single exon, were mixed with 1.1 Mb RNA baits and hybridized for 24 hr, followed by target capture using streptavidin. Enriched targets were sequenced on a HiSeq 2000 system using 49 x 49 paired-end reads. Lockdown probes improved general coverage of GC-rich targets (A) and single GC-rich exons (B).