Albinism Lab Dvolp 1

Albinism: From Genotype to Phenotype Directions Part 1: Read the introduction section on the Canvas page, “Albinism: from Genotype to Phenotype,” and answer the questions below. 1 in 20,000 exhibit this disorder 1. About how many people do they estimate suffer from albinism? _______________________________ 2. Why is melanin important for humans? By not making this, what is a major consequence for people with albinism? It protects the DNA in the cells nucleus from getting damaged by UV light mainly from the sun. People that have albinism are unable to make this due to the pigmentation on their skin, eyes, and hair. Making those with albinism disorder higher risk for skin cancers. 3. Referencing to your answer to #2, why does it make sense that people that live close to equator have a darker skin tone? Due to people near the equator getting more exposure to UV light from the sun. The melanin causes the skin to get darker to protect the DNA in the cells nucleus from sun damage. 4. How many types of albinism are found in humans? There are four types of albinism found in humans. 5. Albinism is caused by a mutation in a gene. Research and describe what a mutation is. Lastly, describe how a mutation can cause a frameshift in an amino acid sequence. Mutation Definition: Change in the DNA sequence of a cell causing different genotype and phenotype of a organism, virus, etc. Frameshift in Amino Acid Sequence: Codons are translated into specific amino acids thus if a mutation has an insertion or a deletion of the nucleotide it could result in an alteration of the reading frame. Resulting in a completely changed amino acid sequence. Mutation Type Description Addition/Insertion A type of genetic change that involves the Deletion Substitution Silent Does it Cause A Frameshift? Yes addition of a segment of DNA. A type of genetic change that involves the absence of a segment of DNA. Type of mutation in which one nucleotide is replaced by a different nucleotide. A change in the sequence of nucleotide bases which constitutes DNA. Yes No No 6. What mutation types (addition, deletion, substitution) do you think can be a silent mutation? Explain your reasoning. I think that a small incorrect protein like AAA turning into AAG is a silent mutation because it results in the same protein being created. 7. Organize your thoughts: by reviewing the phenotypic traits that appear in humans with this genetic disorder in the reading above, complete the table below. White White Peach White Yellow/white White Orange/red Yellow Green African-Americans Blue Saharan-Africans Hazel Dark-skinned Tyrosinase Most people SLC45A2 Brown Tyrosinase Chromosome 15 8. Reviewing your table, what do all types of albinism have in common? Use the traits discussed in the reading as evidence. They all have very light skin. In the reading it says how people with OCA produce small amount of melanin so that is why none of them have dark skin. 9. Construct an explanation below that explains why there are different variations of this disorder and why it results in the same basic phenotype. Cite specific evidence without copying any part of the passage directly below. In the passage it talks about how changes to the MC1R can change some things about the phenotypes of people with OCA too which is why some people have yellow or white hair and others have red hair. Directions Part 2: Procedures: Please read this section after your complete part 1. PLEASE REFERENCE THE AMINO ACID CHART ON CANVAS FOR TRANSLATION 1. Each student will analyze one of four genes: TYR, OCA2, TYRP-1, or SLC45A2. Pick one of the genes and continue on to the next step. 2. Each form has an original DNA strand and 3 different mutated strands. For each, you will transcribe the mRNA sequence and then translate the mRNA into the amino acid sequence (AAs). 3. With a colored pencil, or using an app in which you can draw on, you will then do the following: • First, circle the mutation(s) on each of the three mutated strands that differ from the original DNA strand at the top of your form. (Note: not all sequences start at beginning of gene.) • Second, lightly shade over each codon that differs in the mRNA strand from the original mRNA strand at the top of your form. • Lastly, lightly shade over each amino acid that differs in the amino acid sequence from the original amino acid sequence at the top of your form 4. Using the amino acid sequences, match one of them to the “Individual” cards on the Canvas page to view the phenotype. Once your analysis is complete, fill out the table below. OCA2 1 5 Analysis: Making sense of your data Your gene is: ____________________ Individual # _______ & ______ Mutation Mutation Type Deletion Mutation 1 Mutation 2 Substitution Mutation 3 Substitution Cite Your Evidence Here for Mutation Type In mutation 1, the protein STOP is found in the DNA strand causing everything after it to be cut off. When there is a STOP protein it means deletion. There is a replaced letter that is different than the one in the Gene Affected? Yes Yes original DNA strand. There is a replaced letter that is different than the one in the original DNA strand. No Mutation Table Questions: 1. Which of the mutations caused a change in phenotype? WHY? Mutation 1 causes a change in phenotype because there is a deletion which changes a lot of the original DNA. 2. Which mutation type did NOT cause a change in phenotype? WHY? Mutation 3 because it has the same proteins as the original Directions Part 3: Flow Chart for Protein Synthesis: By creating a flow chart below, trace the steps from DNA through to the resulting phenotype. It has been started for you below. BEFORE completing your flow chart, please watch the video in Canvas under the albinism lab page referenced earlier. The following words must appear in this flow chart: Translation Amino acid(s) Protein Gene mRNA tRNA Phenotype Transcription mRNA Phenotype Gene a tRNA Translation Amino acids Protein Riley AUC GUG CAC AGA ACU CUG GCG GCC AUG CUG GGU UCC CUU GCA GCA CUG GCA GCA CUG GCU lle Val His Arg Thr Leu Ala Ala Met Leu Gly Ser Leu Ala AUC GUG CAC UGA ACU CUG GCG GCC AUG CUG GGU UCC CUU GCA lle Val His STOP Thr Leu Ala Ala Met Leu Ser Gly Leu Ala Ala Leu Ala Ala Leu Ala GCA CUG GCA GCA CUG GCU Ala Leu Ala Ala Leu Ala I AUC GUG CAC AGA ACU CUG GCG GCC AUG CUG GGU UCC CUU GCA GCA CUG GCA GCA CUG GUU lle Val His Arg Thr Leu Ala Ala Met Leu Gly Ser 1 AUC GUG CAC AGA ACU CUG GCG GCC AUG CUG GGC UCC lle Val His Arg Thr Leu Ala Ala Met Leu Gly Ser Leu Ala Ala Leu Ala Ala Leu Val I CUU GCA GCA CUG GCA GCA CUG GCU Leu Ala Ala Leu Ala Ala Leu Ala