Why ethno-driven screening is best

Ethno‑driven bioprospecting starts from traditional knowledge—plants already used by local communities for medicine, food, dyes, or poisons.

• This pre-selects species that likely contain bioactive compounds, greatly increasing the “hit rate” and reducing time, cost, and scale of random screening.

• Many modern drugs (e.g., aspirin from willow, anticancer drugs from Catharanthus roseus) were discovered via such ethnobotanical leads.

Therefore, for initial screening of plants, the ethno‑driven approach is regarded as the most effective.

Option-wise explanation

1. Ecological studies

   • Can suggest plants with interesting defenses or interactions (e.g., herbivore resistance), but as a primary screening tool, it is broad and slower than directly using human experience.

2. Ethno driven – correct

   • Uses ethnobotany/ethnopharmacology to choose candidate plants already known to have biological effects, making it the best and most practical first step in bioprospecting.

3. Comparison of DNA sequence

   • Useful for taxonomy, phylogeny, or identifying biosynthetic genes once candidates are known.

   • Not an efficient starting method because similar DNA does not guarantee similar metabolites or activities.

4. Comparison of protein sequence

   • Relevant in molecular biology and enzyme evolution, but not a practical field‑level screening tool for novel plant resources; requires prior knowledge and lab data that bioprospecting usually does not have at the outset.

Thus, ethno‑driven screening (option 2) is the best method for initial selection of plants in bioprospecting.