D-HaploDB: a database of definitive haplotypes determined by genotyping complete hydatidiform mole samples.

The Definitive Haplotype Database (D-HaploDB) is a web-accessible resource of genome-wide definitive haplotypes determined from a collection of Japanese complete hydatidiform moles (CHMs), each of which carries a genome derived from a single sperm. Currently, the database contains genotypes for 281 439 common SNPs from 74 CHMs which were determined by a high-throughput array-based oligonucleotide hybridization technique. The database also presents maps of haplotype blocks and linkage disequilibrium bins together with tagSNPs that might prove useful for association studies of disease genes. Cryptic relatedness among the samples in this study is unlikely, because the formation of a CHM is a maternal event of rare sporadic occurrence, and its genotype is that of the incoming sperm. This is demonstrated by the absence of long extended shared haplotypes (ESHs). The D-HaploDB is freely accessible via the Internet at http://orca.gen.kyushu-u.ac.jp.