Location of Markers

[billmartin]

a. I see loci listed with "location numbers" of 388-607. I assume they start numbering at one. How many "locations" are there in total ?

b. When the lab looks at a DNA sample, after it has been processed and prepared for analysis, how do they find, for example, location 393? [that is, where do they measure from and how do they measure to location 393?]

c. A 12-marker analysis uses the 12 locations 393, 390.........392, 389-2.
What is special about those 12 that they are used as the initial locations to examine?
And a similar question: why are the next 13 chosen as the 25-marker locations to examine rather than locations in the last 12 [for a 37-marker analysis]? In other words, what's special about each of these three sets of locations?

d. It is my understanding that the 37 locations now being used as Marker locations [and that I've observed are numbered intermittently from 388-607] have been selected from experience.
[Researchers have simply observed that these locations are useful for genealogical purposes, if I read the tutorials correctly].
If that is correct, does it mean that in the future, additional locations might be discovered to also be useful for genealogy?

Thank you for helping me understand.

-Bill Martin

[billmartin]

A partial answer

Since no answers to this Query were posted on this Forum, I searched elsewhere and found partial answers from a posting on the Genealogy-DNA-L list at Rootsweb.com
I pass them along for those of you who are interested.

http://www.cstl.nist.gov/biotech/strbase/ystrpos1.htm

-Bill Martin

[Khachtex]

Thanks, Bill, I'll check rootsweb, I use it so much didn't think about checking for a DNA message board.

Your questions were good ones, I was looking forward to a response!

[A.Hunt]

This board suppose to be a place where people signed up for result to communicate. They mention while back not ot expect a person employeed with FTDNA to respond ot thread. I will admit that they do in fact and will respond from time to time.

I am not sure total number of marker in Y-DNA but I do know htey look for marker that has a very low chance of mutating. With this slowness in mutation it help build branches in very large surname projects.

a) no answer

b) Once again I might be wrong. I seen what appear to be a signal on oscilloscope with a signal. I assume they take these signal point to decide. Again I am just a customer as well. I do not work in genetic research.

c) The reason for different branches is while DAN genealogy is a new technology they are discovering new marker and how often if at all the marker mutation rate.

d) From a email listing some marker are not listed as number but as letters. Apparently there a group called HUGO who assigned the marker their numbers. Some of these other marker listed as name haven't been through HUGO requirement for naming.

Again this is all new technology some of the stories from DNA genealogy are quite interesting read.

A.Hunt

[billmartin]

Kachtex, I was in the same boat with you - a big RootsWeb user but never thought about DNA. Now we both know. That Genealogy-DNA-L list gets pretty far off into genetic outer space at times, but there's enough in plain English that I'm learning from it.

A. Hunt, thanks for the help. I had missed the FTDNA post about no normal staff help on this forum. Your answers helped me.

-Bill Martin

[AngelaC]

a. I see loci listed with "location numbers" of 388-607. I assume they start numbering at one. How many "locations" are there in total ?

b. When the lab looks at a DNA sample, after it has been processed and prepared for analysis, how do they find, for example, location 393? [that is, where do they measure from and how do they measure to location 393?]

c. A 12-marker analysis uses the 12 locations 393, 390.........392, 389-2.
What is special about those 12 that they are used as the initial locations to examine?
And a similar question: why are the next 13 chosen as the 25-marker locations to examine rather than locations in the last 12 [for a 37-marker analysis]? In other words, what's special about each of these three sets of locations?

d. It is my understanding that the 37 locations now being used as Marker locations [and that I've observed are numbered intermittently from 388-607] have been selected from experience.
[Researchers have simply observed that these locations are useful for genealogical purposes, if I read the tutorials correctly].
If that is correct, does it mean that in the future, additional locations might be discovered to also be useful for genealogy?

Thank you for helping me understand.

-Bill Martin

Hi Bill,

Just a quick response for now,

I've just returned from holiday so my brain isn't quite in "DNA mode yet" - but when it is i'll give you better answers (particularly for b).

a) Presumably more than 600 (with new ones being found all the time)
b) I believe they "locate" them using specific DNA sequence "primers" (I'll answer this much better later)
c) I think its more a matter of the order in which researchers discovered/used them for anthropological studies, and or discovered/decided that they would be useful for genealogical purposes. The markers in the first 12 include some of those used in the earliest anthropological DNA studies, and those in the last 12 include some newly "discovered" markers.
d) Yes

Angela.

[billmartin]

Location of Markers

Angela, thank you for your answers and observations to my questions. They were quite helpful in aiding my understanding of this DNA subject.

I was unable to respond to you as quickly as I had hoped...something is wrong with my Netscape 7.2 browser and it won't display the "Log In" link for me to enter my User Name and Password. As a result, the FTDNA Forum wouldn't let me post a reply to you. I still don't know why that's happening, so today I tried switching to my Internet Explorer browser - with success. [I wasn't ignoring you.]

Are you recovered yet from holiday? I surely hope you had a good time.

And thanks again for your tutoring.

-Bill Martin Denver, CO, USA

[jmarshal]

Location of Markers

Perhaps this may be a fairly good answere to your question in a).
www.ensembl.org/Homo_sapiens/mapview?chr=y
and of course to all who are interested.

Greetings
Junior

[billmartin]

Location of Markers

Junior, that's quite a web site you posted. Thanks very much.

-Bill

[AngelaC]

Angela, thank you for your answers and observations to my questions. They were quite helpful in aiding my understanding of this DNA subject.

Are you recovered yet from holiday? I surely hope you had a good time.

Hi Bill,

My Brain is almost recharged (yes it was a good holiday the weather etc. in Italy was wonderful, ..quite unlike the weather here in Denmark )

Hopefully I'll get onto tackling the answer for b) soon (I'm still figuring out how to explain it in a way thats easy to understand & also to verify that my understanding of how they locate markers is correct).

Basically: They identify/locate the markers not by physical location on the chromosome, but matching up an adjacent part of the DNA code, eg ACCTAGC with a "template" of the same bit of code (the "primer").

Angela.