Introduction（material used from Wikipedia）:
Birch trees belong to the genus Betula in the family Betulaceae, which are deciduous hardwood tree. Birches are pioneer species, and can rapidly colonize open ground especially in secondary successional sequences. They often form even-aged stands, and generally distribute in lowland, but some species, such as Betula nana, have a montane distribution. Birch trees are fast-growing woody species that are tolerant to cold, light drought and flooding and adapts well to numerous types of soil. This widely grown tree is important in timber and in the pulp and paper industry. B. pendula is continuously distributed in North Asia and Europe, B. platyphylla Suk, which is considered as geographic variation specie of B. pendula, is widely distributed in north of China, East-Siberia in Russia, Mongolia, Korea, and Japan.
On October, 2013, we complete the first draft genome sequence of a tree of B. platyphylla, which grows in Harbin (China) located at 45°44′N and 126°36′E. The genome of B. platyphylla is sequenced using the next-generation sequencing technology (Illumina GA) and the self-developed short reads assembly method. The genome of B. platyphylla is estimated to be approximately 440 million base pairs contained in 28 chromosomes. Based on the genome of B. platyphylla, we re-sequenced the genomes of B.pendula, B. pendula‘crisp’, B. pendula‘Dalecarlica’ and B. pendula ‘Purple Rain’. We created this database to present the entire B. platyphylla genome sequence, as well as the annotation information such as gene structure and functions, non-coding RNAs and repeat elements. We illustrated the B. platyphylla genome data in a MapView, which is powered by Google Web Toolkit. A new module was developed to browse large-scale short reads alignment. This module enabled users track detailed divergences between consensus and sequencing reads.