C. elegans Epigenetic Inheritance Project

ISEF Category: Cellular and Molecular Biology

Subcategory: Genetics  ·  Difficulty: Advanced  ·  Setup: University Lab  ·  Time: Full Year

The Hook

Some traits can echo past stress long after the stress is gone. In C. elegans, tiny worms can pass on gene activity changes across generations, almost like a molecular memory. That makes them a powerful model for testing how environment shapes inheritance. Your project asks whether heat stress changes fertility in a way that lasts.

What Is It?

Transgenerational epigenetic inheritance means a trait changes in the next generation, even when the DNA code itself does not change. Think of DNA as the recipe book, and epigenetics as the sticky notes that tell the cell which pages to read more or less often. In C. elegans, these sticky notes can include small RNAs and other gene regulation marks.

RNAi-by-feeding is a way to turn genes down using bacteria. The worms eat E. coli that make a double-stranded RNA matching one target gene. That RNA tells the worm cell to silence the matching gene. You can then compare brood size, which is the number of offspring a worm produces, across treated and untreated lines and across generations after heat stress.

Why This Is a Good Topic

This topic works well for a science fair because it has a clear question, a measurable outcome, and a real biology connection. You can test whether an environmental stress leaves a trace that shows up later in fertility, which links genetics, gene regulation, and inheritance. The project also teaches you how to work with controls, generational tracking, and quantitative data, which are all strong research skills.

Research Questions

• How does heat stress affect brood size in the first generation after exposure?
• What is the effect of RNAi knockdown of a candidate stress-response gene on brood size after heat stress?
• Does reduced fertility persist in the second generation after heat stress is removed?
• To what extent do different RNAi target genes change the size of the multigeneration effect?
• Which recovery condition best preserves the inherited brood-size change across generations?
• How does the timing of heat stress during development affect later brood size?

Basic Materials

• Live C. elegans culture and a standard wild-type strain.
• E. coli HT115 bacterial strain for RNAi feeding.
• Public RNAi clone or plasmid source matched to a target gene.
• NGM agar plates prepared for worm culture.
• Incubator or temperature-controlled chamber for worm growth.
• Stereomicroscope for worm transfer and brood counts.
• Platinum wire pick or disposable worm pick.
• Micropipettes and sterile tips.
• Parafilm or plate sealing film.
• Dissecting microscope camera or phone adapter for documentation.
• Notebook or spreadsheet for tracking generations and brood size.
• Gloves, disinfectant, and biohazard disposal supplies.

Advanced Materials

• Multiple C. elegans strains with reporter or mutant backgrounds.
• Verified RNAi feeding clones from an Ahringer-style library partner source.
• Temperature-controlled incubator with tighter stability.
• Fluorescence microscope for reporter readouts, if available.
• qPCR access for checking stress-response gene expression.
• Microcentrifuge and RNA extraction kit.
• Agarose gel electrophoresis setup for validation steps.
• Plate reader or imaging station for higher-throughput scoring.
• Statistical software access for mixed-effects or lineage analysis.
• Controlled environmental chamber for temperature comparison experiments.

Software & Tools

• Google Sheets: Organizes brood counts, generation labels, and control groups in one place.
• R: Runs statistical tests, plots line graphs, and compares lineage effects.
• ImageJ: Measures worm size or image-based colony features if you add imaging data.
• GraphPad Prism: Fits curves and compares groups if your lab already has access.
• PubMed: Helps you find review articles and recent studies on epigenetic inheritance in worms.

Experiment Steps

1. Define one primary phenotype, such as brood size, and decide which generations you will track.
2. Choose a candidate stress-response gene or small panel of genes that fits RNAi-by-feeding.
3. Plan your control groups so you can separate heat effects, feeding effects, and true inheritance effects.
4. Design a scoring system that gives you the same measurement method for every generation.
5. Set up a data table before you start, so each worm line, treatment, and generation has a clear label.
6. Build an analysis plan that compares treated lines with controls across generations, not just within one plate.

Common Pitfalls

• Mixing up generations, which breaks the lineage and makes inheritance claims weak.
• Scoring brood size with inconsistent timing, which changes the apparent fertility result.
• Letting plate conditions drift, which can make temperature effects look like gene effects.
• Using weak RNAi targets without validation, which can produce a false negative.
• Comparing only one treated line to one control line, which leaves you unable to tell whether the pattern is real or strain-specific.

What Makes This Competitive

A stronger version of this project would test more than one gene, more than one stress level, or more than one worm strain. You would also need clean lineage tracking and a plan for statistics that handles repeated measurements across generations. If you can pair brood-size data with one extra readout, such as a reporter signal or gene-expression check, your story gets much stronger. The best projects answer a narrow question very cleanly, then show why the result matters beyond one plate.

Project Variations

• Test whether starvation stress, instead of heat stress, produces the same multigeneration brood-size pattern.
• Compare two RNAi target genes, one linked to stress response and one linked to reproduction, to see which better changes inheritance patterns.
• Add an imaging-based fertility proxy, such as embryo count per worm, to compare with brood-size scoring.

Learn More

• WormBook: Free expert-written chapters on C. elegans biology and methods, found by searching the WormBook site.
• NIH PubMed: Search for review articles on transgenerational epigenetic inheritance in C. elegans.
• NCBI Gene: Look up gene function, aliases, and related literature for candidate RNAi targets.
• WormBase: Find strain data, gene models, and phenotype records for C. elegans.
• MIT OpenCourseWare: Search for genetics and molecular biology course materials that explain gene regulation and inheritance.