The highlight for 2005/6 in population genetics was undoubtedly the publication of HapMap, a freely available public resource nearly of all common (>5% minor allele frequency) genetic differences in humans. Compared to the estimated 10 million single nucleotide polymorphisms (SNP) that we all share, at the launch of HapMap in 2002 there were fewer than 1.7 million SNPs on the public database dbSNP. Today, largely due to HapMap and related efforts, that number is around 9.2 million. Furthermore, investigators no longer need to tediously resequence their chosen candidate genes to find the common variants, but can rather spend a few minutes on www.hapmap.org. The data can also be downloaded to select only those tagSNPs that efficiently represent all the other variants in your chosen region. Of course, only a minority of these SNPs will alter gene expression or function. The main limitations of this resource are that it does not cover: 1) rarer although possibly important functional genetic variations; 2) large-scale genomic variations (see paper by Bellanne-Chantelot below); 3) other populations may possibly be less well-represented by the four populations genotyped by HapMap. However we may already be seeing the fruit of increasing numbers of larger and more comprehensive genetic association studies. Examples are the remarkably strong and consistent associations between the TCF7L2 gene and adult type 2 diabetes (1), and within Pediatric Endocrinology the growing number of positive associations reported with childhood obesity (see below).