Read the Genome by Sequence and Scale
Genome projects combine whole-genome sequencing with annotation and distinguish total DNA from protein-coding sequence.
Living-system questions are solved by matching a structure or organism to its function, process and stated condition.
Remember genome-scale facts
The human genome contains about 3.2 billion nucleotide bases; less than 2% codes for proteins. Gene sizes vary; the old estimate of 80,000–100,000 genes was superseded by a much lower count.
Compare sequencing strategies
Sequence annotation aims to read and map genomic segments across coding and noncoding regions. Expressed sequence tags focus on expressed genes/transcripts, so they provide a narrower view.
Separate genome from transcriptome
The genome is the full DNA sequence, whereas the transcriptome is the set of RNA transcripts expressed in a cell at a particular time. It reflects active genes and varies among cell types and physiological states; mature mRNA does not retain introns as part of its sequence.
OlympIQ exam lens
- ✓About 3.2 billion bases; <2% protein-coding.
- ✓ESTs focus on expressed sequences.
- ✓Do not reuse the obsolete 80,000–100,000 gene estimate.
Genome size is not the same as protein-coding sequence size.
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