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In the DNA \"Haystacks\" below you are given a normal DNA strand and it\'s alter

ID: 166968 • Letter: I

Question

In the DNA "Haystacks" below you are given a normal DNA strand and it's altered but similar DNA strand. Your first job is to analyze each pair and identify and name the type of genetic "alteration". Next, use the mRNA codona Amino Acid chart to decode both strands and identify exactly how the "alteration" changed or confused "genetically coded message". Normal "Sense" Strand Tilde ATGAAAAACAAGGTACACATCTAG mRNA Strand Tilde _______ Polypeptide Tilde _______ Altered "Sense" Strand Tilde ATGAAAAACAACGTACACATCTAG mRNA Strand Tilde _______ Polypeptide Tilde _______ Circle the "altered" section and identify the kind of alteration: _______ Normal "Sense" Strand Tilde ATGAAAAACAATTGCACGTAG mRNA Strand Tilde _______ Polypeptide Tilde _______ Altered "Sense" Strand Tilde ATGAAAAACAATTGCACGTG mRNA Strand Tilde _______ Polypeptide Tilde _______ Circle the "altered" section and identify the kind of alteration: _______

Explanation / Answer

Ans. A. #1 Normal “Sense strand”: ATGAAAAACAAGGTACACATCTAG

The sequence of mRNA is exactly the same as sense DNA strand, except T in DNA is replaced by U in mRNA.

            So, mRNA strand = AUGAAAAACAAGGUACACAUCUAG

            Polypeptide: Met- Lys- Asn- Lys- Val- His- Ile- STOP

A. #2. Altered: Normal “Sense strand”: ATGAAAAACAACGTACACATCTAG

mRNA strand = AUGAAAAACAACGUACACAUCUAG

            Polypeptide: Met- Lys- Asn- Asn- Val- His- Ile- STOP

            Point mutation, Missense mutation (A mutation that changes type of amino acid being coded).

B. #1. Normal “Sense strand”: ATGAAAAACAATTGCACGTAG

mRNA strand = AUGAAAAACAAUUGCACGUAG

            Polypeptide: Met- Lys- Asn- Asn- Cys- Thr- STOP

B. #2. Altered “Sense strand”: ATGAAAAACAATTGCACGT //A// G    Note: - //A// deleted

mRNA strand = AUGAAAAACAAUUGCACG UG

            Polypeptide: Met- Lys- Asn- Asn- Cys- Thr-

            Deletion mutation, frameshift Mutation (changes reading frame due to insertion or deletion of one or more nucleotides, not 3 or its multiple).