Most human diseases are results from a complex mixture of 
inherited and environmental factors; the etiology underlying 
these diseases presents a new set of challenges to scientists in 
human genetics. In the past two decades, a huge amount of resources
have been devoted to human disease gene mapping. Numerous positive
results have provided excitement in the field; however, most of 
them fail to be confirmed in subsequent replications. 

Recently, genome-wide association studies (GWAS) using large
sample sizes have become feasible and affordable. By using highly 
dense marker sets and information from the HAPMAP project, the
knowledge of human genome structure, population genetics and
disease-associated variants have been vastly increased. In the 
past two years, there have been many studies adopted GWAS design,
however, despite highly significant p-value, the related odds 
ratios for susceptible alleles were modest. To cope with GWAS, new 
statistical methods have also been developed to help revealing 
possible etiology of complex traits. On the other hand, new typing 
technology emerged continuously. 

In this talk, the following issues will be discussed. 1) Rational 
of GWAS; 2) coverage and efficacy of commercial whole genome make 
sets 3) some recent GWAS and their findings; 4) the follow up of 
GWAS.