Hind III Biology Question?

Question

Hind 111 recognizes a sequence of six nucleotides (AAGCTT) as a cut site. What are the odds that this sequence will occur in a random chain of DNA?

Answer 1

The chain must say A (1/4 chance), then A (1/4 chance), then G (1/4 chance), then C .... and so on.

So the chance of this sequence occurring in a random chain of DNA is 1/4^6 = 1/4096.

Answer 2

Isn't Hind site 2020? LOL

Ya, as mentioned
HindIII is a six-cutter
4^6= every 4096 bp.

Some organisms methylate their DNA,
GC for example.
Some R.E.s don't cut the methylated form.
For HindIII, don't remember off the top of my head.
Check your product guide.

DNA sequence is never totally random.
Some organisms are AT rich, esp. in non-coding regions.
some are GC rich, esp. in the genes.
Thus AAGCTT would favor an AT rich.

I once used a 8-cutter (every 65,536bp)
to try to avoid cutting up a ~3,000 bp gene.
Well, damn thing cut twice in the gene!!!
How unlucky was that!!!

Answer 3

Who says that DNA is random?
anyway you can look at thisas a pure probability issue. What is the probability of obtaining AAGCTT. Given thath there are only 4 nucleotides in DNA (ignoring the methylation aspect) you can comput the probability or AAGCTT as independent event ocurring together, which should be in your text book