16S Sequencing
            A microbiome library was constructed from the tissues of five groups of oysters according to the concentration used in treatments, 30ug atrazine, 10ug atrazine, 3ug atrazine, 30ug acetone, and control group reads were de novo assembled together. The differential expression of microbes was analyzed using the general assembly as a reference for mapping the reads from each condition. In this project, 408,495 pair-end reads were obtained for 16 samples in total, after pair-end reads merging and filtering, 302,751 clean tags were generated, an average of 18,922 clean tags for each sample. Amplicons were performed on a paired-end Illumina HiSeq2500 platform to generate 250bp paired-end raw reads, and then pretreated. Specific processing steps are as follows:
1)  Paired-end reads were assigned to a sample by their unique barcode, and the barcode and primer sequence were then truncated. 

2)  Paired-end reads were merged using FLASH (V1.2.7,http://ccb.jhu.edu/software/FLASH/ ) ,a very fast and accurate analysis tool to merge pairs of reads when the original DNA fragments are shorter than twice of the reads length. The obtained splicing sequences were called raw tags. 

3)  Quality filtering was then performed on the raw tags under specific filtering conditions of Trimmomatic v0.33 (http://www.usadellab.org/cms/?page=trimmomatic) quality control process. After filtering, high-quality clean tags were obtained. 

4) The tags were compared with the reference database (Gold database, http://drive5.com/uchime/uchime_download.html) using UCHIME algorithm (UCHIME Algorithm. (http://www.drive5.com/usearch/manual/uchime_algo.html) to detect chimeric sequences, and then the chimeric sequences were removed. The data output of the above steps is shown in Table 1.
 
High quality reads were obtained from experimental groups “Orange 30” ________________, “Pink 10” _______________, “Green 3”_________________ Acetone 30, and ________________ from the control group. The general microbiome of the Crassotrea virginica tissue samples was assembled in a total of __________ base pair reads. The general microbiome revealed bacteria thought to be involved in pathways related to immunity, and normal cell functioning. 
Results