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Below is a short sequence of DNA showing the mutation that causes B-thalassemia. Which of the following DNA mutations causes B-thalassemia?
Normal B globulin allele --------- AAC CAG AGG
B glbulin allele (thalassemia) --- AAC TAG AGG
a) Frameshift
b) Insertion
c) Missense
d) Nonsence
e) Silent
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it is single nuclutide ,,,,it is missense ,,c,,
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5'-AAC TAG AGG-3' this is the DNA sequence showing the strand which is not transcribed.
Consider the following:
5'-AAC TAG AGG-3'
3'-TTG-ATC-TCC-5'
The bottom strand is transcribed as follows:
3'-TTG-ATC-TCC-5' DNA
5'-AAC-UAG-UGG-3' RNA
Now you have UAG, a stop codon in the RNA. No translation beyond that, so its NONSENSE mutation .
UAG;UAA;UGA are stop codon
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5-AAC TAG AGG-3=CODE DNA STEAND
3-TTG ATC TCC-5=TEMPLATE STRAND
5-AAC UAG UGG-3=mRNA,,,,,,IN WHICH UAG=STOP CODONE
MY MISTAKE IS I THOUGHT GIVEN CODE IN Q WAS mRNA
ANY WAY VERY NICE EXPLINATION ...THANK YOU
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@raheem....missense mutation is when there is a change in single nucleotide (third position of codon).
