Why are my DNA sequence bases upper and lowercase after importing DNA sequences?

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After importing DNA sequences from Ensembl, some regions are uppercase and some are lowercase 


Molecular Biology application - All systems and versions


Ensembl, the online genomic database, represents bases in repeat regions of the gene with lower-case letters. This is called soft-masking. It is an aesthetic choice they made to denote repeat regions of a gene.

Resolution Steps

To change the capitalization:

  1. Highlight the section or entire sequence.
  2. Right-click the highlighted section or sequence, then select Change case.

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