Chromosome 21 is the smallest human chromosome, the long arm
of which comprises 34 MB of DNA sequence. The completion of its nucleotide
sequence revealed 225 genes. It is associated with a number of human pathologies such as Down syndrome, as well as several monogenic
and complex genetic disorders.
Here we present a comprehensive cSNP (Single Nucleotide Polymorphisms within cDNA sequences)
database and map which was generated using a combination of bioinformatics and experimental approaches (see methods),
using the complete DNA sequence and the large amount of ESTs present in the public databases.
The cSNPs will undoubtedly become important tools in genetic
epidemiology studies for the dissection of complex disorders.