Combinatorial pooled sequencing:experiment design and decoding

Owing to rapid advances in the next-generation sequencing technology,the cost of DNA sequencing has been reduced by over several orders of magnitude.However,genomic sequencing of individuals at the population scale is still restricted to a few model species due to the huge challenge of constructing libraries for thousands of samples.Meanwhile,pooled sequencing provides a cost-effective alternative to sequencing individuals separately,which could vastly reduce the time and cost for DNA library preparation.Technological improvements,together with the broad range of biological research questions that require large sample sizes,mean that pooled sequencing will continue to complement the sequencing of individual genomes and become increasingly important in the foreseeable future.However,simply mixing samples together for sequencing makes it impossible to identify reads that belongs to each sample.Barcoding technology could help to solve this problem,nonetheless,currently,barcoding every sample is costly especially for large-scale samples.An alternative to barcoding is combinatorial pooled sequencing which employs pooling pattern rather than short DNA barcodes to encode each sample.In combinatorial pooled sequencing,samples are mixed into few pools according to a carefully designed pooling strategy which allows the sequencing data to be decoded to identify the reads that belongs to the sample that are unique or rare in the population.In this review,we mainly survey the experiment design and decoding procedure for the combinatorial pooled sequencing applied in rare variant and rare haplotype carriers screening,complex genome assembling and single individual haplotyping.