The bacteriophage ϕX174 has a single-stranded DNA genome...

Question

The bacteriophage ϕX174 has a single-stranded DNA genome of 5386 bases. During DNA replication, double-stranded forms of the genome are generated. In an effort to create a restriction map of ϕX174, you digest the z-stranded form of the genome with several restriction enzymes and obtain the following results. Draw a map of the ϕX174 genome.

Pstl 5386 PstI + PsiI 3078, 2308
Psil 5386 PstI + DraI 331, 1079, 3976
Dral 4307, 1079 PstI + DraI 898, 1079, 3409

Accepted Answer

Welcome back, everybody. Here's the next problem. Restriction and nucleases are enzymes that recognize and cleave certain DNA sequences. Which of the following is a restriction site for ECO R one. And we've got four different answer choices here with different base pair sequences. So we're going to think about possibilities for an eco eco R one restriction site. We know that it has a palindromic site. So it should be the same forward and backwards. And the site for ECO R one is G A A TT C. So we can see that if we write our complimentary sequence down here underneath C TT A A G, we've got this palindromic sequence and ECO R one cuts between the G and the A. So you can see when it cuts here, it leaves sticky ends, you're gonna have an overhang. And that makes it useful for cloning for inserting pieces of DNA where you can match up the matching sticky ends. So eco R one is a really common restriction enzyme used in molecular biology. So let's look over at our answer choices to find the corresponding sequence. And we see that in choice D written from five prime to three prime G A A TT C. And that is our correct restriction site for the restriction under nucleus eco R one. See you in the next video.

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