Plantago Species ID With DNA and Leaf Shape

ISEF Category: Plant Sciences

Subcategory: Systematics and Evolution  ·  Difficulty: Intermediate  ·  Setup: Home Setup  ·  Time: 1 to 2 Months

The Hook

Some plants look like twins but are not the same species. That can hide real biodiversity in plain sight. You can find those hidden groups by comparing DNA barcode data with leaf shapes from herbarium photos. This project turns your local Plantago plants into a real detective story.

What Is It?

Cryptic species are species that look very similar but are genetically different. Think of them like two phones with the same case but different parts inside. In Plantago, leaf shape alone may not separate every group, so you can compare physical traits with DNA barcode sequences to see whether the plants cluster into distinct lineages.

The DNA side uses barcode regions such as trnL and ITS. A barcode is a short DNA stretch that can help identify species, like a grocery barcode helps identify a product. The shape side uses herbarium photos, which are preserved plant images from museum or university collections. You measure traits like leaf length, width, and shape ratios, then check whether those measurements match the DNA groups.

Why This Is a Good Topic

This is a strong science fair topic because you can ask a clear question, collect public data, and do real analysis without a university lab. You are testing whether local Plantago samples split into hidden groups when you compare DNA and leaf shape. That connects to biodiversity, species identification, and how scientists spot overlooked organisms. You can learn sequence analysis, morphometrics, and basic statistics in one project.

Research Questions

• How does leaf shape vary among local Plantago herbarium specimens from different collection sites?
• What is the effect of geographic distance on trnL or ITS sequence similarity among local Plantago samples?
• Does combining leaf-shape morphometrics with DNA barcode data separate Plantago specimens into more groups than either method alone?
• To what extent do herbarium photo measurements agree with GenBank-based species assignments for Plantago specimens?
• Which leaf-shape features best predict DNA-based clustering in local Plantago populations?
• How does specimen age or image quality affect the accuracy of leaf morphometric measurements from herbarium photos?

Basic Materials

• Computer with internet access.
• Spreadsheet software such as Google Sheets or Excel.
• PubMed, GenBank, and herbarium database access through a browser.
• Ruler or calibration reference for photo scaling.
• Free image analysis software such as ImageJ.
• Local herbarium photos or digitized specimen images.
• Notebook for specimen metadata and collection notes.

Advanced Materials

• Access to a university herbarium or digitized voucher database.
• DNA sequence alignment software such as MEGA or MAFFT.
• R with morphometric and clustering packages.
• GIS software for mapping specimen locations.
• High-resolution scanner or camera for new specimen imaging.
• PCR and sequencing access if you plan to generate your own barcodes.
• Micropipettes, gel electrophoresis setup, and standard molecular biology supplies.

Software & Tools

• ImageJ: Measures leaf length, width, angle, and shape traits from herbarium photos.
• Google Sheets: Organizes specimen metadata, measurements, and sequence notes.
• R: Runs clustering, correlation tests, and simple morphometric statistics.
• MEGA: Aligns barcode sequences and compares genetic distance among samples.
• BLAST: Checks whether GenBank sequences match known Plantago references.

Experiment Steps

1. Define the Plantago group you will study and decide whether you are comparing one local region, several nearby sites, or public herbarium records.
2. Build a specimen list from GenBank and herbarium databases, and set clear rules for which records you will include or exclude.
3. Choose a small set of leaf traits that you can measure consistently from photos, then plan a calibration method for image scale.
4. Align the DNA barcode sequences and decide how you will turn sequence differences into species or cluster assignments.
5. Compare the DNA clusters with the leaf-shape measurements, and plan a statistical test that checks whether the two data types agree.
6. Prepare a control analysis that checks whether image quality, missing data, or uneven sampling could change your conclusion.

Common Pitfalls

• Mixing specimens from too many Plantago species, which makes the project too broad to interpret.
• Using herbarium photos with no scale bar, which prevents accurate leaf measurements.
• Trusting GenBank labels without checking sequence quality, which can pull in misidentified records.
• Choosing leaf traits that overlap too much, which leaves you with noisy morphometric results.
• Skipping a plan for missing sequence data, which can shrink your sample size and weaken your comparison.

What Makes This Competitive

A competitive project does more than list differences. It tests whether DNA and shape data agree, then asks where they do not. Strong projects use careful specimen filtering, clear clustering methods, and a statistical test for agreement or mismatch. The best versions also explain why hidden diversity might matter for local biodiversity surveys or plant ID tools.

Project Variations

• Focus on one local Plantago species complex and compare urban, suburban, and wild populations.
• Use only herbarium photos and test which leaf traits separate species best without DNA data.
• Add ecological data, such as habitat type or elevation, to see whether environment helps explain shape differences.

Learn More

• NCBI GenBank: Search Plantago trnL and ITS records, then read the linked sequence metadata and publications.
• NCBI BLAST: Compare your barcode sequences against reference records in GenBank and check likely matches.
• US National Herbarium and other digitized herbarium portals: Find specimen photos and label data, often through museum collection websites.
• MEGA: A free sequence analysis package for alignment, distance checks, and basic phylogenetic trees.
• ImageJ: A free image analysis tool from the NIH that helps you measure leaf traits from herbarium photos.
• OpenStax Biology 2e: Review species concepts, phylogeny, and biodiversity basics in a free textbook.