Refer to the table showing several prokaryote (bacterial) species (labeled A-E) that have been sequenced, along with the findings of the genes they contain.(Note: "x" marks the species possessing a functional copy of the gene.) Gene 1 is essential for the synthesis of several amino acids.Gene 2 encodes a protein involved in strengthening the cell wall.Gene 3 produces an enzyme that breaks down methane.The functions of the other five genes are currently unknown. 
What type of study best characterizes what the researchers did?
Definitions:
Brand Equity
The value and strength of a brand that decides its worth and influences consumer choice.
Marketing Value
The perceived worth that a product or service brings to a consumer in comparison to its cost.
Financial Value
The monetary worth attributed to an asset, company, or financial instrument based on its ability to generate income or profits.
Harvesting Approach
A business strategy focusing on extracting maximum profits from a product, market, or investment with minimal reinvestment, often in the decline stage of its lifecycle.
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