DISCOVERING HISTORY OF FOSSILS
STEPPING STONES TO DISCOVER THE UNKNOWN.
Scientists have discovered an unknown fossil in China. Very little is actually known about the fossil; the only given information is that it contains soft tissue and DNA nucleotides. Thus, the main investigative objective of this lab is to find out where the organism fits on the cladogram, after analyzing 4 given genes through BLAST software. A Cladogram is a type of branching diagram that’s very useful to show cladistic relationships between a number of species. Common ancestry is used to determine how closely organisms are related. The more closer two organisms are on the cladogram, the more features they share. Analyzing all 4 genes, and determining which animals they’re located in can guide us through where this unknown fossil actually belongs.
Four main gene sequences found in the fossil are to be given to the student so that they can analyzed completely using BLAST software. These genes other animal's traits and proteins incorporated in the gene that will help deduce the characteristcs of the unknown organism. We must then identify the closest relatives of the fossil specimen gene sequences. The first gene was present in the Gallus gallus (chicken) is comprised of gene called Collagen type V Alpha-1. This collagen is significant because it's part of the fibrillar collagen family. The crocodile organism also has the same exact gene. This could mean that the unknown species shares a relation with the crocodiles and the birds. However, the most closest gene was indeed the Zebra finch gene and it's also alone with the unknown gene on one strand of the cladogram. The organization of the two genes display show that the unknown is most likely closest to the Zebra finch. The last gene is that of a fruit fly shared its gene with a wide variety of animals showing that it doesn't have the correct place for the unknown on the cladogram. Using the information from the the cladogram, the student must then make a logical educated guess about which gene best describes the fossil. Using this knowledge, the four genes were listed in order from most important to least important: Zebra Finch, Gallus Gallus, Crocodile, Fruit Fly.
Using the information from the the cladogram, the student must then make a logical educated guess about which gene best describes the fossil. Using this knowledge, the four genes were listed in order from most important to least important:
Zebra Finch, Gallus Gallus, Crocodile, Fruit Fly.
Methodology and Experimental Design:
2. Then, go to a BLAST link and download all four gene files. http://blogging4biology.edublogs.org/2010/08/28/college-board-lab-files/
3. Next, go to the BLAST home page and click on “Saved Strategies” at the left hand corner of the page.
4. Click on “Browse” and then select of one your downloaded gene files. After doing this, click view.
5. A screen will later show up, in which you can see that the gene sequence has already been selected. Scroll to the bottom, and then click BLAST.
6. A page with two major sections will appear next. The first section will include a display of the matching sequences. Other section is titled “Sequences producing significant alignments” .
7. Click on the first link, as generally what’s on the top is most similar and similarity decreases as you go down the list of sequences.
8. You will get a very detailed report which includes the species’ classification history, and the sequences that align with this gene.
9. You can also click on the “Distance Tree of Results” at the top of this page, to see a cladogram with species with similar sequences to your gene, and also understand how closely their matched genes align with your research gene.
Gene Sequence 1:
Nearest Relative: Fruit Fly
Location of Relative on Branch: On same branch of flies
Protein produced by the sequence : NADH dehydrogenase subunit 6
Unknown close to alligator, crocodiles. etc..
ANALYZING RESULTS: HYPOTHESIS & CONCLUSION CLADOGRAM
Conclusions and Interpretation of Results