1. Department of Computer Science, Hong Kong Baptist University , Hong Kong SAR 999077 , Hong Kong
2. BGI Research , Shenzhen 518083 , China
3. BGI Genomics , Shenzhen 518083 , China
4. BGI Research , Sanya 572025 , China
5. Department of Electrical Engineering, City University of Hong Kong , Hong Kong SAR 999077 , Hong Kong
6. Institute for Research and Continuing Education, Hong Kong Baptist University , Hong Kong SAR 999077 , Hong Kong