Can a Point Mutation and Indel Mutation occur in the same sequence?

[BigEvilRx]

---

Members don't see this ad.

If you have a deletion mutation that removes a single nucleotide in a gene sequence, and all amino acids after change until you reach the UGA codon for stop, are those considered a point mutation (missense specifically) or is it just a frameshift mutation that causes the amino acids to change and appear to be a missense mutation.

Basically, can an indel mutation cause a point mutation?

 

[crazybob]

If you have a deletion mutation that removes a single nucleotide in a gene sequence, and all amino acids after change until you reach the UGA codon for stop, are those considered a point mutation (missense specifically) or is it just a frameshift mutation that causes the amino acids to change and appear to be a missense mutation?

Basically, can an indel mutation cause a point mutation?

My Genetics book from undergrad says:

point mutation A small lesion, usually the insertion or deletion of a single base pair.

missense mutation Nucleotide-pair substitution within a protein-coding region that leads to the replacement of one amino acid by another amino acid.

indel mutation A mutation in which one or more nucleotide pairs is added or deleted.

frameshift mutation The insertion or deletion of a nucleotide pair or pairs, causing a disruption of the translational reading frame.

It wouldn't be missense IMO since one amino acid is missing.

I'd call it a frameshift mutation.

And to your second question, yes.

 

[BigEvilRx]

It wouldn't be missense IMO since one amino acid is missing.

I'd call it a frameshift mutation.

And to your second question, yes.

That is what I was thinking but we were given that frameshift is an indel mutation and missense is one of the point mutations.

That was my gut feeling but I have 11 amino acid changes and didn't know what to make of it.

Thanks.

 

[phathead]

If you have a deletion mutation that removes a single nucleotide in a gene sequence, and all amino acids after change until you reach the UGA codon for stop, are those considered a point mutation (missense specifically) or is it just a frameshift mutation that causes the amino acids to change and appear to be a missense mutation.

Basically, can an indel mutation cause a point mutation?

It's a frameshift mutation, you're moving the reading frame.

rather interesting that you guys are using different terminology than what I studied...

 

[rxlea]

Frameshift.

 

[BigEvilRx]

Thanks to you all. I read up on it a little more and it clarified it for me. I appreciate you leading me in the right direction.

 

[BigEvilRx]

oh crap.

"Such a mutation, called a frameshift mutation, will occur whenever thenumber of nucleotides inserted or deleted is not a multiple of three. All the nucleotides that are downstream of the deletion or insertion will be improperly grouped into codons, and the result will be extensive missense, usually ending sooner or later in nonsense and premature termination. Unless the frameshift is very near to the end of the gene, the protein is almost certain to be nonfunctional."

Can anybody explain this?

So it can be both frameshift and point mutation at the same time?

 

[phathead]

oh crap.

"Such a mutation, called a frameshift mutation, will occur whenever thenumber of nucleotides inserted or deleted is not a multiple of three. All the nucleotides that are downstream of the deletion or insertion will be improperly grouped into codons, and the result will be extensive missense, usually ending sooner or later in nonsense and premature termination. Unless the frameshift is very near to the end of the gene, the protein is almost certain to be nonfunctional."

Can anybody explain this?

So it can be both frameshift and point mutation at the same time?

We always referred to a frameshift mutation as a nonsense mutation because it rid the strand of the stop codon.

Point mutation generally changed the particular AA.

Lemme dig out my genetics book for a quick refresher. I should know this because I did research on genetic analysis for a year lol

 

[phathead]

Ok, a point mutation is the changing of one letter of the codon.

A frameshift mutation is the addition or removal of one letter of the codon.

They are not connected and are not the same.

I'll give you the example my books gives me:

The codon string is: THE CAT SAW THE DOG

If it is a point mutation, you change a letter. Say swap out the C for a B so it reads: THE BAT SAW THE DOG. Notice it's not the same thing, but it still makes sense.

Now lets add a letter: THE CMA TSA WTH EDO G
Or subtract a letter: THE ATS AWT HED OG

Notice neither one makes sense now.

Does that help?

 

[b1234]

Frameshift ddloesn't have to be nonsense. With nonsense you get a codon that doesn't code for anything...

 

[phathead]

Frameshift ddloesn't have to be nonsense. With nonsense you get a codon that doesn't code for anything...

Good point, I was confusing terms. A nonsense mutation is when there is a point mutation so that a stop codon is created.

Dur lol