a) You are studying the human genome, and find a 20bp region which contains over 90% G and C. How unlikely is this? What is the probability that a 20bp sequence will have 18 or greater G's or C's, if A,C,G,and T are distributed equally and randomly in the genome, i.e. 50% G or C? You need to design PCR probes to amplify this region. What minimum length (in bp) should the primer sequences be to expect that they are unique in the human genome (one perfect match)? Assume that ACGT are distributed randomly in the 3x10 bp long human genome (as in (a)). Ignore the complementarity of the genomic DNA strand and the primer.