BRAINCAKEIntrons and Satellite DNA
Most of the genome does not code for proteins. Two types of non-coding DNA are important for this topic.
Introns
In eukaryotes, most genes contain non-coding sequences called introns between the coding sequences, called exons. The whole gene, introns included, is transcribed into pre-mRNA, and the introns are then removed before translation. Introns are found within genes, and their base sequences can vary between individuals without affecting the protein produced.
Satellite DNA
Between genes there are regions where a short base sequence is repeated many times, one after another. These are called tandem repeats or satellite DNA. There are two main types:
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Key terms in this lesson
- phenotype
- The observable characteristics of an organism, resulting from its genotype and its environment.
More in Gene Sequencing
- How PCR Works
- DNA Sequencing
- Using DNA Sequencing
- Using DNA Sequencing to Manage Disease
- DNA Profiles
- Gel Electrophoresis
- Southern Blotting and Gene Probes
- Forensic Science
All 12 lessons in Gene Sequencing · All Edexcel A-level Biology topics