Perl References

Problem Set

1. Create a script that stores the data in a hash of hashes, according to the labels (gene, expression, tissue), so that you can access the data using those labels. For example, if your data structure is called %hash, you should be able to look up the data related the CDC2 gene like this:

   $gene = 'CDC2';
   my $expression_for_gene = $hash{$gene}{'expression'};
   my $tissue_for_gene     = $hash{$gene}{'tissue'};
   

   gene	expression	tissue
   CDC2	45	liver
   PLK1	34.2	heart
   MCM4	9	kidney



2. Modify your script so that the data for MCM4 is printed out like this:
   

   gene     expression    tissue
   MCM4     9             kidney
   

3. Add a new gene, with an expression level, in a tissue.
   
   
4. Modify your script to take the data from a tab-delimited file with many genes with expression data. Be sure to include a few genes that are expressed in the liver. Print this as you did in question 2


5. Print out all genes that are expressed in the liver. Report the average expression level of these genes.