Coding Strand

 This is an ambiguous term, and perhaps best avoided. Because DNA is double-stranded and only one strand of the DNA of a gene is usually transcribed to make RNA, there is a distinction between the transcribed and the nontranscribed strand at any point in the genome. Using the useful terminology “upstream”/“downstream” to refer to the direction in which the gene is transcribed and translated, the nontranscribed DNA strand runs upstream to downstream in the chemical direction 5′ to 3′, whereas the complementary transcribed strand has the opposite 3′ to 5′ polarity. The transcript RNA runs 5′ to 3′, like the nontranscribed DNA strand. Thus, the nontranscribed DNA strand matches the mRNA in its base sequence (with thymine replacing uracil), not the transcribed strand which has the back-to-front complements of the codons, as explained in Figure 1. Consequently, in predicting encoded amino acid sequence of the encoded protein from a gene DNA sequence, one uses the sequence of the nontranscribed DNA strand because this is the strand from which the codons can be read directly. For this reason, the nontranscribed strand is sometimes called the coding strand.

Some workers, however, adopt the opposite convention because, after all, the transcribed strand provides the information for the codon sequence of the mRNA. Therefore, it is best to eschew the coding versus noncoding terminology and to distinguish the two DNA strands as transcribed versus nontranscribed.

It should be remembered that both strands of a particular segment of DNA can be transcribed, though probably never in the same cell type and at the same time. This may be the case, for example, when genes are “nested” within the introns of other genes  .

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العتبة العباسية المقدسة تنظّم مسيرات عزائية لإحياء ذكرى عاشوراء في نينوى

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يجب أن تأكل المزيد من الشمام هذا الصيف.. إليك السبب ؟

تأثير صحي كبير.. كم بيضة يجب أن تتناول يوميا؟

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أداء خلايا البيروفسكايت الشمسية تحت الماء قد يزيد كفاءة تحويل الكهرباء

مسافة الأمان: أساس القيادة الآمنة وتجنب الحوادث

هل القيادة السريعة تعني استهلاك اكثر للوقود؟

لماذا يعتبر كوكب المريخ غير صالح للحياة؟

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مواضيع ذات صلة

Site for Cro Repression and CI Activation

Chronology of Becoming a Lysogen

N Protein and Antitermination of Early Gene Transcription

Spontaneous Mutations in bacteria

Mechanisms of Gene Transfer in Bacteria

Phage Replication

Genotoxicity Through Potential Off-target Nuclease - Induced Double - Strand Breaks

A Broad Range of Genomic Changes by Homologous Recombination–Mediated Genome Editing

Early Transcription of Genes N and Cro

Lambda’s Relatives and Lambda Hybrids

The Genetic Structure of Lambda

The Physical Structure of Lambda