Considering that extensively duplicated genes, especially for the large tandem gene clusters, have always been difficult regions in genome assembly and remain incomplete as gaps in genomes, GDOS focused on using high-quality genomes (T2T/gap-free genomes are the most preferred) assembled by the third generation long-read sequencing technologies, such as the HiFi sequencing, to ensure the reliability and accuracy of all identified dosage genes. GDOS will continue to be updated and expanded as more gap-free genomes become available.