Lesson 279

Bioinformatics &<br>Computational Biology

sequences · alignment · BLAST · assembly · trees

1:00

How classic algorithms — sequence alignment, BLAST, genome assembly, and phylogenetic trees — make biological data computable, from DNA strings to protein 3-D structures.

By the end, you can

  • Describe DNA, RNA, and protein as strings and explain the central dogma flow.
  • Explain why sequence alignment is more appropriate than exact string matching for comparing biological sequences.
  • Fill in a small Needleman-Wunsch DP table and perform a traceback to read off the optimal alignment.
  • Distinguish global alignment (Needleman-Wunsch) from local alignment (Smith-Waterman) and choose the right one for a given problem.
  • State why O(m·n) DP is impractical at genome scale and explain how BLAST's seed-and-extend heuristic addresses this.
  • Interpret a BLAST E-value and explain why a low E-value indicates a significant hit.
  • Explain how de Bruijn graphs reduce genome assembly to an Eulerian path problem, and contrast this with the OLC approach.
  • Distinguish UPGMA from Neighbor-Joining as phylogenetic distance methods.
  • Describe what AlphaFold2 achieved and why protein structure prediction was considered a grand challenge.
Up next in String Algorithms, Advanced DP & Competitive Techniques
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