Question

Identify the organism whose genome has not been sequenced.

• A. Caenorhabditis elegans
• B. Arabidopsis
• C. Drosophila
• D. Sea urchin

Hint:

Model organisms sequenced under HGP:
$\bullet$ Nematode: Caenorhabditis elegans
$\bullet$ Insect: Drosophila melanogaster
$\bullet$ Plants: Arabidopsis thaliana, Rice (Oryza sativa)
$\bullet$ Microbes: Yeast (S. cerevisiae), E. coli

Answer 1

The Correct Option is D

Concept:
The Human Genome Project (HGP) not only sequenced human nuclear DNA but also sequenced several non-human model organisms to understand basic biological processes, comparative genomics, and evolutionary relationships.

Step 1: Genome Projects of Non-Human Model Organisms in NCERT:
During the Human Genome Project, several non-human model organisms had their complete genomes mapped and sequenced due to their immense utility in genetic, physiological, and developmental research.
The prominent non-human organisms listed in canonical biological curricula whose genomes were successfully sequenced include:
1. Bacteria (e.g., Escherichia coli)
2. Yeast (Saccharomyces cerevisiae)
3. Caenorhabditis elegans (a free-living non-pathogenic nematode whose genome was completely sequenced)
4. Drosophila melanogaster (the fruit fly)
5. Plants such as Arabidopsis thaliana and Oryza sativa (rice).

Step 2: Evaluating the Non-Sequenced Organism:
- Option (A) Caenorhabditis elegans: Genome fully sequenced as an essential model for developmental biology and cell lineage.
- Option (B) Arabidopsis: Genome fully sequenced as a classical plant genetic model.
- Option (C) Drosophila: Genome fully sequenced as a classical model organism for eukaryotic genetics.
- Option (D) Sea urchin: Although sea urchin is studied in classical embryology, it is not among the benchmark model organisms sequenced and highlighted as part of the Human Genome Project curriculum.

Step 3: Final Answer:
Thus, among the given choices, the organism whose genome is not cited as sequenced under the HGP model organisms curriculum is Sea urchin.