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Definitions

Genome Sequencing:  A variety of laboratory procedures that provide detailed information about the genetic makeup of infectious disease pathogens (germs) that are making people sick. 

 Gene: A specific sequence of DNA or RNA found at a specific location in a genome. Each gene encodes a function within the human body or other organisms (for example, there are specific genes that produce eye color). 

 Genome: All of the DNA or RNA found in a cell or virus.  

 Mutation: A change in the genetic sequence of DNA or RNA where nucleotides have been altered, inserted, or deleted.  

 Phylogenetic Tree: A tree-like diagram that shows mutational differences between sequenced DNA or RNA.  These diagrams show evolutionary changes and genetic relationships between organisms over time. 

The illustration above shows a sketch of a transmission tree with a subset of cases that were sampled.
The illustration above shows a sketch of a transmission tree with a subset of cases that were sampled (A-E). The colored dots indicate mutations between samples. Source: How to read a phylogenetic tree

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Last Updated: August 14, 2025