Daniel H. answered • 02/28/21
UC Davis Graduate Specializing in Genetics
Hello Shyla
So this one is a bit hard to conceptualize, but I want you to start by drawing a circle which is your plasmid, and then try to identify the restriction sites by marking them based on bp length. It can be a tough progress, but its made a bit easier by the combinations listed. For example, the Eco RI excises a strand of 4363 bp, but when used in combination with Pvu, it creates two strands of lengths 2296 and 2063. Added together, this makes 4363, so from that we can write on the circle two Eco RI sites, and a bit more than halfway inbetween we can identify a site for Pvu. By using these combinations, you can find the distance between restriction sites, and see what fits where. I hope this helps.
Daniel H.
Not quite. For using Eco RI alone we see that there is only one fragment generated. This means that I was wrong in my previous assessment. The cleavage site generated must be the entire plasmid length. This means that there is only one site, and that it just cuts the entire plasmid open.03/01/21
Shyla H.
I'm still a little confused by the concept. All of the combinations equal 4363, so am i going to have more that 2 Eco RI sites. I need 4 cut sites.03/01/21