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Genomes and Maps module of the MLA course on Introduction to Molecular Biology Information Resources
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Genome Assembly

NCBI Contig Assembly and Annotation Process: The process used to assemble the contigs and annotate the sequence is complex and continuously being refined. The linked page gives a detailed description of the NCBI approach.

Data Preparation

  • Input data includes both finished and draft genomic sequence data from GenBank
  • Data is screened for contamination by bacterial and viral sequences
  • Sequence is compared to other genomes, such as the mouse
  • Repeats are masked

Contig Construction

  • Clone layout stage
  • Sequence building stage
  • Melds of overlapping sequences formed and ordered
  • Contigs are placed on a chromosome using sequence overlaps with mapped STS markers and paired BAC-end sequences.

Genomes and Maps
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Revised 11/07/2007