Unit 3 Lab Notes: DNA Fingerprinting in Elephants

Introduction

  • Objective: Explore the use of DNA fingerprinting in elephants to combat poaching.

  • Overview: DNA analysis can help identify specific elephant populations targeted by illegal hunting.

Lab Preparation

  • Accessing Materials:

    • Navigate to Unit 3 Lab Material on the blackboard site.

    • Scroll down to Lab 15 focused on DNA fingerprinting in elephants.

    • Computers are available for use, and students can work in pairs if needed.

DNA Fingerprinting

  • Definition: Each elephant has unique DNA that can be sequenced to identify its population.

  • Components of DNA:

    • DNA consists of nucleotides with bases adenine (A), thymine (T), cytosine (C), and guanine (G).

    • Complementary base pairing rules: A pairs with T, C pairs with G.

Importance of Elephants

  • Elephants are classified as the largest land mammals and a keystone species.

  • Keystone Species Definition: A species whose removal from the ecosystem leads to significant ecological collapse.

  • Conservation Status:

    • Estimated that 50,000 elephants are killed yearly.

    • Current estimates indicate less than 470,000 elephants remain in Africa.

    • Illegal hunting primarily targets elephant tusks for ivory trade, contributing to organized crime.

Forensic DNA Analysis

  • Purpose: Analyze large ivory seizures to trace the source population of poached elephants.

  • Seizure Definition: Large ivory shipments weighing at least half a ton, valued over a million dollars.

  • Analysis Goals:

    • Identify regions in Africa where poaching and organized crime syndicates operate.

    • Facilitate targeted law enforcement interventions to combat wildlife trafficking.

DNA Analysis Techniques

Short Tandem Repeats (STR)

  • Definition: STRs are short sequences of DNA that repeat multiple times.

  • Uniqueness: Each elephant has distinct STRs which can be linked to individual animals.

  • Application: Used in paternity tests and wildlife forensics.

Polymerase Chain Reaction (PCR)

  • Definition: A laboratory technique used to amplify specific segments of DNA.

  • Purpose of PCR: Generate multiple copies of a desired DNA sequence.

  • Three-Step Process of PCR:

    1. Denaturation: Heating the DNA to separate its strands.

    2. Annealing: Binding short sequences (primers) to the target DNA.

    3. Extension: DNA polymerase adds complementary nucleotides to amplify the DNA.

  • Result: From one double-stranded DNA, many copies are produced through multiple cycles (typically around 30).

Gel Electrophoresis

  • Definition: A technique for separating DNA fragments based on size.

    • Gels act as sieves; smaller fragments move faster than larger ones.

  • Setup: Samples are loaded into wells of an agarose gel, and an electric field is applied to facilitate migration.

  • Reference Points: A ladder provides a size reference for DNA fragments (e.g., 100, 250, and 500 base pairs).

  • Interpreting Results: Bands appear on the gel indicating sizes of amplified DNA; similar band patterns suggest related individuals (used in forensic analysis).

Conclusion

  • Students will conduct hands-on applications of the concepts discussed: working with DNA analysis tools in solving poaching cases using interactive online resources.

  • Next Steps: Proceed to open the Bio Interactive platform and tackle case one and two as part of today's lab activities.