The motivation to sequence the genome of an organism usually stems from its relevance in the scientific or medical community:
- There are many species (organisms) that are relevant to public health, agriculture, the food and drug industries, and wild life preservation because they are pathogens or parasites that can infest the environment — including potable water — and food sources. They can cause diseases in humans, animals or plants (examples).
- Other investigators focus exclusively on the human genome to uncover its sequence variants, especially those that cause genetic disorders. In addition to the genetic disease focus, the curated and annotated human genome reference assembly has been an invaluable aid to a vast range of other biomedical research projects.
- Instead of studying all organisms in a taxonomic group, researchers often rationalize and choose a single species to study as a proxy, or "model," for the related organisms. Some study genomes of those model organisms that relate to certain aspects of human biology or diseases and can be used in laboratory experiments (examples).
- Organisms’ economic importance also make them candidates for genome sequencing (for example domestic animals, field crops, organisms for industrial use).
- Also on the list of relevance are genomes of those organisms that are used to address questions about evolution, phylogeny, and natural diversity.