Definition- dna profile + recombinant DNA + primer

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Death Adder
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Definition- dna profile + recombinant DNA + primer

Post by student12 » Tue Jun 20, 2006 11:00 am

Can somebody see if i help me define these terms:

DNA profile: refers to the unique lengths of DNA fragments of an individual as a result of gel electrophoresis?

Recombinant DNA: does it refer to the total DNA with a new DNA, or just the new DNA only?

primer: does it refer to the RNA strand containing the hydroxyl group, or just the 3'end hydroxyl group?

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Inland Taipan
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Post by canalon » Tue Jun 20, 2006 1:39 pm

DNA profile: yes and no. The different size are not an intrisic property of DNA, it has to be treated before, either digested (usually with a rare cutter enzyme, just like in PFGE) or amplified by PCR with a given set of primers.

Recombinant DNA: both depending of the context. Yeah I know... :(

Primer: It's a stretch of nucleic acid (either "man made" DNA for PCR or RNA for natural priming during replication), and it is not just the 3'OH, even if this is the group allowing the priming of the reaction.

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Post by majik1213 » Fri Jun 30, 2006 5:01 pm

Recombinant DNA - refers to the total DNA. Remember, DNA replication is semiconservative. This means that for every replicated double helix DNA, there is an old strand and a newly synthesized strand. That in mind, consider the meaning of recombinant DNA. Basically you have endonucleases that cut DNA at specific points. As a result, there are loose fragments of DNA floating around in the solution. Most restriction endonucleases cleave the DNA strand unevenly, leaving complementary single stranded ends. THese ends can reconnect through hybridization and are termed sticky ends. Once paired, the phosphdiester bonds of the fragments can be joined by DNA ligase. These two joined strands have essentially recombined the DNA sequences, and hence we refer to the resulting double helix DNA as recombinant DNA.

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