BRAINCAKEThe Genome
The genome is all of the genetic material in an organism. In humans it is the complete DNA base sequence in one set of chromosomes, including the small circular DNA found in mitochondria.
The human genome contains about 3.2 billion base pairs, organised into 23 pairs of chromosomes in most body cells. Only about 20,000 of these sequences are genes that code for proteins, and less than 2% of the genome codes for protein. The rest is non-coding DNA, which includes regulatory sequences that control when genes are switched on, sequences that code for functional RNA, and long stretches of repeated sequences.
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Key terms in this lesson
- allele
- One of the alternative forms of a gene, occupying the same position (locus) on a chromosome.
More in Gene Sequencing
- The Polymerase Chain Reaction
- How PCR Works
- DNA Sequencing
- Using DNA Sequencing
- Using DNA Sequencing to Manage Disease
- Introns and Satellite DNA
- DNA Profiles
- Gel Electrophoresis
All 12 lessons in Gene Sequencing · All Edexcel A-level Biology topics