GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2002-01 > 1010598493


From: Terrence Carmichael <>
Subject: Re: [DNA] Medical DNA tests
Date: Wed, 09 Jan 2002 09:54:38 -0800
References: <9d.213e1bca.296dae83@aol.com><042e01c1992d$02a60fa0$5622343f@computer>


Not really, Martha. But what you are saying shows that you do understand what you
are thinking.

The alleles would actually be the 'sub-alleles' that you describe. Blood types are
really a phenotype of a specific sequence. Therefore, the genotype of the phenotype
(e.g. antigen B of the ABO blood-types) may be variable. For example, SNPs are
single point mutations (at one base pair), and may offer no change in the
polypeptide (protein) sequence (or 3 dimensional configuration required for the
proteins activity) that is produced from the DNA (gene) sequence. Therefore, many
alleles may be responsible for expressing the phenotype, antigen B. Explaining the
detailed reasons for this will take up the rest of my day. So, I will end this
response here. However, ...

... I think one company that has potential to do a fraction of what Mr. Paul Cuni
has brought up (one medical test for all genetic diseases) is Sequenom
(http://www.sequenom.com/). They already have a SNP test that can detect 100s of SNP
markers that have 'known' to be associated to diseases such as cardiac disease,
different cancers, and more. An extensive report on the SNPs that you have is
provided, and also gives you a personal at-risk assessment of your health. I,
personally, think that the 'actual' usefulness of this is too premature to
calculate, but it is a grreat start with greater potential.

Terry Carmichael
GeneTree DNA Testing Center, San Jose, CA
www.genetree.com



Martha Smith wrote:

> So you're saying that 'medical DNA testing' even for a single gene like CF
> isn't as easy as it sounded at first? Kind of like tissue matching and
> blood types, there's more there than meets the eye. Like each allele may
> have an array of several to many sub-allele's or 'hidden' allelic group
> attached to it?
>
> Martha
>
> ----- Original Message -----
> From: <>
> To: <>
> Sent: Wednesday, January 09, 2002 8:32 AM
> Subject: Re: [DNA] Medical DNA tests
>
> > In a message dated 01/09/02 4:41:44 AM Pacific Standard Time,
> > writes:
> >
> >
> > > How long do you think before a general medical DNA test will be
> available
> > > that may test u for a hundred or so conditions? I know there are
> specific
> > > tests now for various conditions but what about a general test?
> >
> > It's going to be a pretty tricky proposition. I saw a press release last
> fall
> > about one condition, cystic fibrosis. This is a disease caused by a defect
> in
> > a single gene, but look how complicated it is to screen for it, then
> multiply
> > that for conditions which involve multiple genes!
> >
> > http://www.genzyme.com/ir/genz/press/20011002.html
> >
> > "Since the CF transmembrane regulator (CFTR) gene was first isolated in
> 1989,
> > scientists have identified more than 900 mutations associated with cystic
> > fibrosis, most of which are rare. The DNA test offered by Genzyme Genetics
> > screens for 87 cystic fibrosis gene mutations, including the 64 most
> common
> > mutations and 23 rarer ones. Screening for a larger group of mutations
> > provides a test that is sensitive to the genetic differences among the
> > ethnically diverse U.S. population, according to a study that Genzyme
> > Genetics scientists recently published in Genetics in Medicine. Screening
> for
> > a larger number of mutations especially helps identify more carriers among
> > Hispanics and African-Americans, the study found."
> >
> > ______________________________
>
> ==============================
> To join Ancestry.com and access our 1.2 billion online genealogy records, go to:
> http://www.ancestry.com/rd/redir.asp?targetid=571&sourceid=1237




This thread: