Hello Steve,

I don't think I would be able to explain it better than one of those 
ready made tutorials available online.

Take a look at a couple of links:

http://www.dnaheritage.com/tutorial1.asp (follow the series)
http://www.familytreedna.com/dna101.html

As you know, the Y chromosome has segments of genetic material that 
pass practically unchanged from father to son, except in those rare 
cases where a mutation occurs.  The numbers you ask about represent a 
count of the so called Short Tandem Repeats or STRs at specific 
locations in the DNA molecule.  When a mutation happens the count of 
STRs can increase or decrease usually by one count.  These mutations 
tend to accumulate over generations at varying rates which can help to 
calculate or approximate the "genetic distance" between two related 
persons who share a common ancestor. I don't know if I'm being clear 
enough so I'll stop here!  Anyway, read some of those documents online 
and then come back to share your thoughts again.

Victor


--- In ranchos@yahoogroups.com, "Steve G. Apodaca" <sgapodaca@y...> 
wrote:
> After all this conversation, I got really interested about submitting 
> my DNA as well as my Tapia DNA through an uncle. Another member and 
> possible primo (Angel Cervantes) encouraged me to do it in the past. 
> Well, in the next couple months I will probably get several samples 
> from different family lines. (As soon as I get the cash for it)
> 
> I just have a question, maybe I just need to read Gary Felix's 
website 
> more carefully. Is there a table or something that explains what do 
> all those numbers on the tables mean? Also, what is the difference 
> between 12, 25 and 37 marker? What does it mean?
> 
> Steve.