gene copy numbers

Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.

Moderators: Leonid, amiradm, BioTeam

Post Reply
psychic_pizza
Garter
Garter
Posts: 7
Joined: Mon Mar 05, 2007 12:41 am

gene copy numbers

Post by psychic_pizza » Tue Mar 06, 2007 4:03 am

I have to do a presentation about applications in Molecular biology. However, the only part I'm stuck on is gene copy numbers. I don't really understand what they are?

All I got was that they are repeated copies of some sequences on some chromosomes, and they are the casue of phenotypic diversity.

so the repeated sequences differ between individuals, right?

.Are they just random sequences in random palces that are repeated, or are they specific for something?

.How can southern blotting (is that what's used?) be used to detect them?

I understand SNPS (and I think it's related?)

it would be appreciated if you have a diagram to explain it, becasue I just can't visualize what they are.

Any help would be appreciated!!!

Vagabond
Death Adder
Death Adder
Posts: 59
Joined: Mon Feb 19, 2007 7:01 pm

Post by Vagabond » Tue Mar 06, 2007 1:26 pm

typically since humans are diploid organisms you should have 2 copies of each gene. I think you are confusing SNPS and such which are associated with genes.
A SNP is Single Nucleotide Polymorphism. There are also regions called:
STRs or short tandem repeats these are short repeated patterns of two or more nucleotides. The repeats vary and are polymorphisms.

One can occasionally track a disease by following a known and liked STR or SNP.

Southern blotting is a classical way of screening and detecting these polymorphisms in samples.
Ok I know that does not answer everything but I have to get going but I hope it helps.
---------------------------------------

You know dog spelled backwards is god.
Coincidence? I think not. . .

psychic_pizza
Garter
Garter
Posts: 7
Joined: Mon Mar 05, 2007 12:41 am

Post by psychic_pizza » Thu Mar 08, 2007 3:27 am

Thanks for the reply.

I still don't understand what gene copy numbers are though.
You said that since humans are diploid organisms you should have 2 copies of each gene. So the gene copy numbers are "extra" copies?

thanks.

go&go
Garter
Garter
Posts: 4
Joined: Wed Jan 17, 2007 3:59 pm

Post by go&go » Thu Mar 08, 2007 3:46 pm

from wikipedia

The gene copy number (also "copy number variants" or CNVs) is the amount of copies of a particular gene in the genotype of an individual. Recent evidence shows that the gene copy number can be elevated in cancer cells. For instance, the EGFR copy number can be higher than normal in Non-small cell lung cancer.

In certain cases, such as rapidly growing Escherichia coli cells, the gene copy number can be 4-fold greater for genes located near the origin of DNA replication, rather than at the terminus of DNA replication. Elevating the gene copy number of a particular gene can increase the expression of the protein that it encodes.


hope u can understand now by that.

operon
Garter
Garter
Posts: 9
Joined: Mon Feb 12, 2007 11:35 pm

Post by operon » Thu Mar 08, 2007 8:07 pm

My understanding of it is that all humans (and probably most vertebrates?) have in that DNA specific repeated sequences. These repeats, I believe, arose when a certain part of the DNA was cut out(let's call it A) and then inserted at another part (let's say two units indicated as - -) so then you'd get something like A - - A now let's say this part is cut up and reinserted somewhere else, maybe 4 units down: A - - A - - - - A - - A. I'm not sure if this is what happened but it makes sense to me. The reason these things are there is because it doesn't really matter. There's no reason to get rid of them because they're just useless repeats. It's good in a way because it leaves a bunch of useless pieces of information inbetween the good stuff so if there was a mutation, chances are it would occur in the useless stuff.

Southern blotting is used to "see" just what kind of repeated sequences are in a person - this is the DNA banding thing that you've seen in CSI and everything. People who have the same bands in the same positions have that same piece of DNA - ie. they have the same repeated sequence. Now imagine that people typically have a whole lot of these repeats - chances are no one has the same repeats, so you can use this to distinguish between individuals.

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests