1. What kind of research is exon sequencing suitable for?

There are about 180000 exons in human genome, and the size of exon CDs region accounts for 1-2% of human genome, about 30 MB. The protein coding region of human genome contains about 85% of pathogenic mutations. Exome sequencing is mainly aimed at the detection of coding region, so exome sequencing is mainly suitable for the study of diseases caused by potential mutation of coding region. Sequencing is cost-effective, especially suitable for high-depth and large-scale sequencing, which can find common mutations and low-frequency mutations. It is mainly used in the research of Mendelian genetic disease and tumor.

2. What types of mutations can exon sequencing detect?

Exon capture is a process of hybridization capture. The hybridization efficiency of probe and different exon segments is not the same, and the coverage depth of different exon segments is different, so exon sequencing can not be used to detect CNV. But we can detect SNP, indel and CNV variation for a single sample by using international mainstream software and long-term optimization analysis method.

3. Why do cancer genome sequencing usually select cancer tissue and adjacent tissue / blood samples from the same patient in pairs?

Cancer genomics focuses on the study of somatic mutations caused by tumor cell specific and non genetic factors, so we need to select the normal tissues of patients for sequencing to filter germline mutations. Because of the great difference of germline mutations among individuals, in order to avoid screening many pseudopositive somatic mutation sites, tumor and normal tissues need to come from the same individual.