Practice 4. Genefinding
   
Gene
finding
exercise
 

In this exercise we will run a genomic DNA sequence against some gene prediction programs, and we will analyze the differences between predictions and annotations of the real gene.

1. Tools

  • geneid (gene prediction program)
  • Genscan (gene prediction program)
  • MetaGene (gate to several gene prediction program)

2. Get seq. and annotation
  • Get the DNA sequence: HS307871
  • Get the annotations (EMBL input)

3. Run geneid
  • Connect to the geneid server
  • Paste DNA sequence
  • Run geneid with different parameters:

    1. Searching signals: Select acceptors, donors, start and stop codons. Look for them in the real annotation of the sequence

    2. Searching exons: Select All exons and try to find the real ones

    3. Finding genes: You do not need to select any option (default behaviour). Compare the predicted gene with the real gene

  • ANALIZE THE RESULTS

    Predicted sites Predicted exons Predicted genes


4. Run Genscan
  • Connect to the Genscan server
  • Paste DNA sequence
  • Run Genscan

6. Compare Predictions

Compare geneid and Genscan predictions checking this plot


7. Run Metagene
  • Connect to the MetaGene server
  • Fill in sequence name and e-mail address (not compulsory)
  • Paste DNA sequence
  • Run MetaGene
  • Wait for a couple of minutes, monitoring the search process
  • Check Current Search Results
  • Annotate Results
  • Tools: Statistics summary
  • Tools: Analysis

N E X T

Enrique Blanco García © 2002