in literature I found two sets are commonly used by different researchers. I need to know that which set should I prefer and why? These are the two sets spa-1113f (5`-AAAGACGATCCTTCGGTGAGC-3`) and spa-1514r (5`-CAGCAGTAGTGCCGTTTGCTT-3`) and 1095 F: 5′-AGAC GATCCTTCGGTGAGC-3′ and 1517R: 5′-GCTTTTGC AATGTCATTTACTG-3′