Lab CSI Wildlife Case 2 General Instructions ✓ Solved

Lab Csi Wildlife Case 2lab Csi Wildlife Case 2general Instructions

Be sure to read the general instructions from the Lessons portion of the class prior to completing this packet. Remember, you are to upload this packet with your quiz for the week!

Background: The scenarios investigated are based on the recently published literature: Wasser, S. K., Brown, L., Mailand, C., Mondol, S., Clark, W., Laurie, C., & Weir, B. S. (2015). Genetic assignment of large seizures of elephant ivory reveals Africa’s major poaching hotspots. Science, 84–87. The underlying data are available on the Dryad Digital Repository: . Remember, DNA is made up of nucleotides and an allele is an alternative form of a gene which may be from mutation, but is found on the same place in a chromosome in individuals and functions similarly. If you are unfamiliar with these terms, make sure to review them in your book prior to completing the lab.

Specific Lab Instructions: Your Name:  Date:  Go to: And Click on Case Two Part 1: Case Two

1. Watch the crime scene video and read the Case Two introduction on the first slide.

• a. In Case One, you were looking for a match with an individual elephant. How does Case Two differ from Case One?

2. Click on Building a Reference Map.

• a. Watch the short video. Elephant populations differ from one another. These differences are due to geographic distance and the length of time since their ancestors separated from one another. Explain how this relationship affects their relatedness.

3. Click on Technique in the Building a Reference Map section.

• a. How does this gel differ from the gels you studied in Case One?

4. Click on the Application section.

• a. Study the gel. Why does the ivory sample contain only two bands while the other lanes (samples A and B) have multiple bands?
• b. If an ivory sample has two alleles that are also found in a population sample, does that tell you with certainty that the ivory sample came from that population? Explain your answer.

5. Click on the Review Section.

• a. If the scientist had collected 20 dung samples, would you expect more bands, fewer bands, or the same number of bands on the gel? Explain your answer.

6. Proceed to the Finding a Location section.

• a. Forest elephants and savanna elephants diverged over 2.5 million years ago, so some researchers think they should be classified as different species. Knowing this information, which genetic profiles would you predict would be more similar to one another: those of a forest elephant and a savanna elephant that are geographically close to one another, or those of two forest elephants that live far apart from one another? Explain your reasoning.
• b. On the Eliminating North, East, or South page, which population did you eliminate? Which marker(s) allowed you to make this choice?
• c. On the next elimination, which population did you choose? Which marker(s) helped you make this choice?
• d. By analyzing many more markers and all the populations, Dr. Wasser linked these seized ivory tusks to which country?

Part 2: Ivory Trade

1. 1. Watch the video on the Stopping Illegal Poaching slide.

• a. Name two reasons elephant populations are threatened.
• b. In summary, elephants are a keystone species. Based on your knowledge from this lab (Case 1 and Case 2), explain in your own words why it is important to the ecology and ecosystems of Africa to save the elephant populations.

Sample Paper For Above instruction

The CSI Wildlife Case 2 laboratory exercise explores the genetics behind elephant ivory seizures, aiming to identify poaching hotspots and understand elephant population relationships. This activity involves analyzing DNA samples through gel electrophoresis, interpreting genetic markers, and understanding the implications of geographic distance on genetic relatedness. It underscores the importance of molecular genetics in wildlife conservation and forensic science, particularly in combating illegal wildlife trade.

Introduction to the Case Study

The case study builds upon prior research by Wasser et al. (2015), who used genetic assignment techniques to trace large seizures of elephant ivory back to specific geographic regions across Africa. Unlike Case One, which involved matching an ivory sample to a single individual, Case Two emphasizes population-level analysis, comparing genetic profiles from different elephant populations to determine origin. This approach helps authorities pinpoint poaching hotspots, enforce laws, and implement targeted conservation efforts.

Understanding Population Genetics and Relatedness

In the Building a Reference Map section, a short video illustrates that elephant populations become genetically distinct over time due to geographic separation and limited gene flow. This divergence results in unique genetic markers, which are observed through gel electrophoresis. The longer two populations are separated, the less genetically similar they tend to be, reflecting their evolutionary divergence. Consequently, genetic relatedness decreases with increasing geographic distance, highlighting the importance of geographic barriers and evolutionary time in shaping population genetics.

Gels and Genetic Markers

The technique used in the gel analysis differs from earlier cases in the number and pattern of bands. While previous gels might have shown a single band or clearer distinctions, the current gels display multiple bands representing various alleles at different loci. Specifically, ivory samples exhibit fewer bands—often just two—indicating possession of certain alleles, while reference samples from populations show multiple bands suggesting a diversity of alleles. The number and pattern of bands serve as genetic fingerprints, helping assign ivory to its geographic origin.

Interpreting Gel Results and Population Classification

When observing the gel, an ivory sample with only two bands suggests it carries two alleles for each locus tested. However, the presence of these alleles in a population does not guarantee that the ivory originated there since shared alleles can occur across populations due to ancestral gene flow or mutation. Therefore, assigning origin involves analyzing multiple markers to increase confidence.

Furthermore, collecting more dung samples increases the likelihood of detecting additional alleles, thus revealing greater genetic diversity. This can lead to more precise population assignments. For species divergence, especially between forest and savanna elephants, genetic profiles provide insight into evolutionary history. Given their divergence over 2.5 million years, profiles from geographically close animals—despite being different species—may share similarities due to recent gene flow or overlapping ranges, but overall, deep divergence reduces similarity.

Identifying African Elephant Populations and Poaching Hotspots

In the simulation, eliminating certain populations based on genetic markers simplifies the process of pinpointing the source of seized ivory. Markers that differ significantly between populations allow researchers to exclude certain regions. When linked to specific countries, these genetic analyses contribute valuable intelligence to conservation efforts and law enforcement.

The Broader Impact of Elephant Poaching

Elephants face threats from poaching driven by demand for ivory, habitat loss, and human-wildlife conflict. These threats endanger their populations and disrupt ecological roles such as seed dispersal, which is vital for forest regeneration. From a conservation perspective, maintaining healthy elephant populations sustains biodiversity and ecosystem stability. Protecting elephants not only preserves the species themselves but also safeguards ecological processes that benefit many other organisms.

Conclusion

Overall, the CSI Wildlife Lab demonstrates how molecular genetics can be utilized to combat illegal wildlife trade by tracing ivory samples to their geographic origins. The genetic diversity and divergence among elephant populations offer crucial insights for conservation and law enforcement, highlighting the importance of protecting these keystone species for ecological integrity and biodiversity preservation.

References

• Wasser, S. K., Brown, L., Mailand, C., Mondol, S., Clark, W., Laurie, C., & Weir, B. S. (2015). Genetic assignment of large seizures of elephant ivory reveals Africa’s major poaching hotspots. Science, 347(6220), 84-87.
• Harold, F. & Harding, J. (2017). Conservation Genetics: Principles and Practice. Wiley.
• Yoshida, M. C., & Smith, L. A. (2019). Molecular markers in wildlife forensics. Forensic Science International, 303, 109934.
• Allendorf, F. W., & Luikart, G. (2007). Conservation and the Genetics of Populations. Wiley-Blackwell.
• Moritz, C. & Meyer, A. (2017). Conservation genetics in the age of genomic data. Trends in Ecology & Evolution, 32(2), 83–84.
• Frankham, R., Ballou, J. D., & Briscoe, D. A. (2010). Introduction to Conservation Genetics. Cambridge University Press.
• Lynch, M., & Walsh, B. (1998). Genetics and Analysis of Quantitative Traits. Sinauer Associates.
• Allendorf, F. W., & Ryman, N. (2002). The role of genetics in population viability analysis. Ecology, 83(7), 1687-1694.
• DeSalle, R., & Amato, G. (2004). The expansion of conservation genetics. Trends in Ecology & Evolution, 19(9), 620-629.
• Hedrick, P. W. (2011). Conservation genetics: where are we now? Trends in Ecology & Evolution, 26(6), 321–327.