Using the blocks database to recognize functional domains.

Blocks are ungapped multiple alignments of related protein sequence segments that correspond to the most conserved regions of the proteins. The Blocks Database is a collection of blocks representing known protein families that can be used to compare a protein or DNA sequence with documented families of proteins. Protocols in this unit describe the analysis of proteins and families using Blocks-based tools, including searching, exploring relationships with trees, making new blocks, and designing PCR primers from blocks for isolating homologous sequences.