How does the HaeIII enzyme discriminate between the C-G polymorphism in the TAS2R38 gene?

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2 answers:

valkas [14]3 years ago

8 0

Answer;

-HaeIII cuts at the sequence GG:CC which is found at nucleotide 143-146 of the TAS2R38 gene. A non-taster alley changes the sequence at position 145 from a C to a G. This makes the gene no longer recognized by the restriction enzyme.

Explanation;

-Restriction enzymes recognize and make a cut within specific palindromic sequences, known as restriction sites, in the genetic code. This is usually a 4- or 6 base pair sequence.

For example; HaeIII is a restriction enzyme that searches the DNA molecule until it finds this sequence of four nitrogen bases.

5’ TGACGGGTTCGAGGCCAG 3’

3’ ACTGCCCAAGGTCCGGTC 5’

Once the recognition site was found HaeIII could go to work cutting (cleaving) the DNA

Xelga [282]3 years ago

7 0

The HaeIII enzyme cuts at the GGCC sequence of the TAS2R38 gene. This sequence is generally present at 143-146 bps. The change in this sequence will lead to a change in the sequence, which won’t be determined by the enzymes. This non-recognition will lead to the absence of the excision.

Further Explanation:

Restriction enzymes work to cut the sequence of DNA at a suitable place by producing a sticky or a blunt cut. A few examples of restriction enzymes are as explained in the figure attached below.

Let us try and understand how exactly the restriction enzymes work;

Suppose a restriction enzyme works on the AATT sequence and gives a cut between AA:TT.
This enzyme, when introduced in the sample, will start working.
The first step will be recognition.
The enzyme will recognize a particular sequence and cut.
In this case, a blunt cut will be introduced in the sample.

If there is a change in the sequence by any chance, the function of recognition will be affected. This will lead to non-recognition of the sequence, thereby rendering the incorporation of restriction enzyme not fruitful.

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