|  |  | 
 
  |  | Genes must be polymorphic
  to generate downstream genetic effects (as opposed to downstream molecular
  effects). Hars2 meets this condition because we have already mapped a
  functional polymorphism in the gene. We can therefore posit that Hars2 is a
  QT gene. What transcripts are downstream? App is one obvious
  candidate, but there are many more. 
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  |  | 
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  |  | The are several ways to
  look for downstream targets. The best and most obvious is to look up all
  transcripts that have high correlations with Hars2 itself. You should know
  how to do this. An alternative method is shown here for teaching purpose and
  to show you what to do if your gene of interest is not in our database. You
  need to know: 
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  |  | 
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  |  | 1. Where your gene is located. You need this information to find a
  surrogate marker; a marker that is located very close to your gene of
  interest. 
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  |  | 2. That your gene is
  polymorphic between C57BL/6J and DBA/2J. 
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  |  | 
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  |  | LetŐs look at the
  correlation of Hars2 with BXD genotypes as shown in the slide above to
  illustrate how to use markers as surrogate traits. 
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  |  | Go to the Trait Date and
  Editing window one more time. We want the data for Hars2 this time, not App.
  You should be able to show that Hars2 has a high  correlation with D2Mit423 as shown in the slide above. 
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  |  | 
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  |  | By clicking on the symbol
  D2Mit423 in the Correlation window, you will generate a new Trait Data window
  shown on the next slide. 
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