Does complementary DNA include only coding sequences ?

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ophelia15
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Does complementary DNA include only coding sequences ?

Post by ophelia15 » Sat Oct 19, 2013 10:25 pm

Hello everyone, I was wondering if complementary DNA is a copy of the entire messenger RNA or only a copy of the coding parts ?
I'm really confused...
For example, if I have the mRNA of a particular gene with some non-coding parts, will the cDNA be exactly the same as the mRNA or it will contain only the coding parts ?

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jonmoulton
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Re: Does complementary DNA include only coding sequences ?

Post by jonmoulton » Mon Oct 28, 2013 3:46 pm

cDNA can contain 5' and/or 3' UTR sequence but not introns.

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JackBean
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Post by JackBean » Mon Oct 28, 2013 5:27 pm

of course it will be reverse complement, but considering the length, it will cover whole mRNA (at least in theory, depending on the primers etc.)
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

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JackBean
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Post by JackBean » Mon Oct 28, 2013 5:28 pm

which reminds me, if you use gene-specific primers, you will only amplify the region you designed the primers for! Which can, but probably doesn't include UTRs
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

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jonmoulton
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Re: Does complementary DNA include only coding sequences ?

Post by jonmoulton » Tue Oct 29, 2013 3:14 pm

Right - another technique, like RACE, is usually needed to extend the sequence across UTRs. If the primers are designed against genomic sequence, they can include UTR sequence, but are unlikely to capture the entire UTRs.

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