function count = pattern(filename);
   fid = fopen(filename,'rt');         % open the file
   if fid < 0
      error(['File ' filename ' not found']);
   end
   genome = fgetl(fid);
   count = 0;
   i=1;
   while i < length(genome)-6
      % Look for the beginning of a gene - starts with TAC
      if genome(i) == 'T' & genome(i+1) == 'A' & genome(i+2) == 'C'
	 % Look for an end of the gene - ends with ACT, ATT, ATC
	 for j=i+3:3:length(genome)-5
	    if genome(j) == 'A'
	       if genome(j+1) == 'T'
		  if genome(j+2) == 'T' | genome(j+2) == 'C'
		     printIt(genome,i,j);
		     break;
		  end
	       elseif genome(j+1) == 'C' & genome(j+2) == 'T'
		  printIt(genome,i,j);
		  break;
	       end
	    end
	 end
	 i = j+3;  % this goes here to prevent infinite loop if end condon
      else         % is not found after a beginning condon
	 i = i+3;
      end
   end
end

function printIt(genome,i,j);
   name = ['from ' num2str(i) ' to ' num2str(j+2) ' (' num2str(j+3-i) '): '];
   if j+2-i > 36
      for k=i:i+15 name = [name genome(k)]; end
      name = [name '...'];
      for k=j+2-15:j+2 name = [name genome(k)]; end
   else
      for k=i:j+2 name = [name genome(k)]; end
   end
   disp(name);
end