PMID- 31888469 OWN - NLM STAT- MEDLINE DCOM- 20200506 LR - 20200506 IS - 1471-2164 (Electronic) IS - 1471-2164 (Linking) VI - 20 IP - Suppl 12 DP - 2019 Dec 30 TI - normGAM: an R package to remove systematic biases in genome architecture mapping data. PG - 1006 LID - 10.1186/s12864-019-6331-8 [doi] LID - 1006 AB - BACKGROUND: The genome architecture mapping (GAM) technique can capture genome-wide chromatin interactions. However, besides the known systematic biases in the raw GAM data, we have found a new type of systematic bias. It is necessary to develop and evaluate effective normalization methods to remove all systematic biases in the raw GAM data. RESULTS: We have detected a new type of systematic bias, the fragment length bias, in the genome architecture mapping (GAM) data, which is significantly different from the bias of window detection frequency previously mentioned in the paper introducing the GAM method but is similar to the bias of distances between restriction sites existing in raw Hi-C data. We have found that the normalization method (a normalized variant of the linkage disequilibrium) used in the GAM paper is not able to effectively eliminate the new fragment length bias at 1 Mb resolution (slightly better at 30 kb resolution). We have developed an R package named normGAM for eliminating the new fragment length bias together with the other three biases existing in raw GAM data, which are the biases related to window detection frequency, mappability, and GC content. Five normalization methods have been implemented and included in the R package including Knight-Ruiz 2-norm (KR2, newly designed by us), normalized linkage disequilibrium (NLD), vanilla coverage (VC), sequential component normalization (SCN), and iterative correction and eigenvector decomposition (ICE). CONCLUSIONS: Based on our evaluations, the five normalization methods can eliminate the four biases existing in raw GAM data, with VC and KR2 performing better than the others. We have observed that the KR2-normalized GAM data have a higher correlation with the KR-normalized Hi-C data on the same cell samples indicating that the KR-related methods are better than the others for keeping the consistency between the GAM and Hi-C experiments. Compared with the raw GAM data, the normalized GAM data are more consistent with the normalized distances from the fluorescence in situ hybridization (FISH) experiments. The source code of normGAM can be freely downloaded from http://dna.cs.miami.edu/normGAM/. FAU - Liu, Tong AU - Liu T AD - Department of Computer Science, University of Miami, 1365 Memorial Drive, P.O. Box 248154, Coral Gables, FL, 33124, USA. FAU - Wang, Zheng AU - Wang Z AD - Department of Computer Science, University of Miami, 1365 Memorial Drive, P.O. Box 248154, Coral Gables, FL, 33124, USA. zheng.wang@miami.edu. LA - eng GR - R15 GM120650/GM/NIGMS NIH HHS/United States PT - Comparative Study PT - Journal Article DEP - 20191230 PL - England TA - BMC Genomics JT - BMC genomics JID - 100965258 RN - 0 (Chromatin) SB - IM MH - Bias MH - Chromatin/chemistry/genetics MH - Chromosome Mapping/*methods MH - Contig Mapping MH - Genome/genetics MH - Reproducibility of Results MH - *Software PMC - PMC6936146 OTO - NOTNLM OT - 3D genome structure OT - GAM OT - Genome architecture mapping OT - Hi-C OT - Normalization OT - Systematic biases COIS- The authors declare that they have no competing interests. EDAT- 2020/01/01 06:00 MHDA- 2020/05/07 06:00 PMCR- 2019/12/30 CRDT- 2020/01/01 06:00 PHST- 2020/01/01 06:00 [entrez] PHST- 2020/01/01 06:00 [pubmed] PHST- 2020/05/07 06:00 [medline] PHST- 2019/12/30 00:00 [pmc-release] AID - 10.1186/s12864-019-6331-8 [pii] AID - 6331 [pii] AID - 10.1186/s12864-019-6331-8 [doi] PST - epublish SO - BMC Genomics. 2019 Dec 30;20(Suppl 12):1006. doi: 10.1186/s12864-019-6331-8.