Independent Variable Lab Report

609 Words3 Pages

Variables
Independent variable – the variable which will be manipulated throughout the investigation is the primary protein structure of the genes that will be compared across the organisms. The primary protein structures of genes which will be compared are insulin (INS), retinal (RPE65), growth hormone (GH1), amylase (AMY1A), and pepsin (PGA5). The entire sequence of the protein of the selected genes will be compared for all the organisms.
Dependent variable – the variable that is affected by the independent variable. In this investigation the dependent variable is the percentage similarity of the primary protein structure of the other mammals to humans. The percentage similarity to humans will be indicated in the final modified result table …show more content…

For example, IGF1 is an insulin like growth factor whereas the INS gene is one of the genes that codes for the hormone.
The full primary structure of the protein was compared. The entire primary protein code of the gene was selected for comparison in the nucleotide blast. Therefore, the varying lengths of the gene code were only recorded for qualitative observations.
The same website were used throughout the experiment It is likely that different websites compare the two gene codes using different algorithms. Therefore, by using the same website for the comparison, it was ensured that the same algorithm was used throughout. Moreover, if the website is rounding up the final figures, the final percentage will be rounded the same time each time.
Same four species of organisms were observed The same four species that were initially chosen were for comparison were used to compare each gene. For example, sus scrofa, i.e. pig was selected for each gene.
All organisms belonged to the same class All the organisms studied belonged to the ‘mammalian’ …show more content…

For example, amylase and pepsin are vital for digestion, therefore comparing these proteins amongst a group of mammals could indicate change in eating habits leading to evolution.
Part 2:
1) The primary structure for proteins (amylase, pepsin, etc) were searched using the NCBI Gene Databank (http://www.ncbi.nlm.nih.gov/)
2) In the search results, a particular variant of the gene was chosen, such as GH1 for growth hormone.
3) Using the advance search option, this particular variant of the gene was searched in the GenBank (eg. INS for insulin or GH1 for Growth hormone) and filtered for the specific species such as sus scrofa (pig) and gorilla gorilla (gorilla)
4) The base sequence was obtained for each gene by searching the NCBI Reference sequence and then choosing ‘FASTA’.
5) The entire sequence was selected and pasted into the nucleotide blast in a second website (http://blast.ncbi.nlm.nih.gov/Blast.cgi?PROGRAM=blastn&PAGE_TYPE=BlastSearch&LINK_LOC=blasthome)
6) In the database option, ‘Others’ was selected.
7) Using the ‘Organisms’ option the results were filtered to show only Homo Sapiens
8) By clicking the ‘Blast’ button at the bottom of the page, the results of percentage similarity were