关键词: 全基因组关联研究, 状态一致（IBS）, 同源一致（IBD）, 病例对照研究, 单核苷酸多态性

Abstract: The present study for locating disease genes by IBD mapping needs to detect IBD segments firstly, and then performs association analysis using the IBD information. But it takes a long time to detect IBD segments. A new algorithm FADG is proposed to find the candidate IBD segments by analyzing the relationship between IBS and IBD, and defines evaluation function to analyze case and control groups separately, the largest difference position of SNP between the two groups is the causative loci. The experimental analysis for effectiveness, based on the five major causative loci of rheumatoid arthritis provided by GAW15 and the data which generated by the program GS, shows the results are consistent with the answer. The algorithm shows higher efficiency in ensuring the effectiveness by comparing with existing method. Finally, the permutation test for two chromosomes from data RA verifies the credibility, and further excludes the possibility of a false positive result.

Key words: Genome Wide?Association Study（GWAS）, Identity By State（IBS）, Identity By Descent（IBD）, case-control study, Single Nucleotide Polymorphism（SNP）