|MadSci Network: Molecular Biology|
Hi Helen, Yes of course DNA is made of 2 strands which are antiparallel but a chunk of DNA will always code for same amino acids depending on its reading frame i.e Only ONE strand out of the two is coding at a moment. Imagine a situation where you have DNA strand 5' AATGCGATA 3' 3' TTACGCTAT 5' In this case, the mRNA formed for upper strand will be UUACGCUAU and for the lower strand will be AAUGCGAUA. Now, if you refer to the Table describing genetic codon (for 1st reading frame), you will find that the amino acids coded by 1st mRNA is Leu Arg Tyr and the 2nd amino acid codes for Asn Ala Ile. So 2 different strands are coding for different amino acids. So there is nothing to get confused. The role of other strand is highly appreciated at the time of DNA repairing i.e. Base excision repair and Nucleotide excision repair etc. I hope i clarified. Regards Tarun Gupta B.Sc (Hons) Bioinformatics Panjab University, India. email@example.com
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