Thank you for pointing out this site to me (http://members.tripod.com/~GaryFelix/index63.htm).This is in fact also a very good website to get a good picture of how DNA genealogy works.
The site uses the open source platform (www.ysearch.org) which FamilyTreeDna (www.familytreedna.com) developed.The former is a website where you may post (on a voluntarily basis) your DNA results to match them with others who did the test with either FamilyTreeDNA or any other company which performs DNA tests.This allows you to compare your results / match them with results from others and, more importantly, communicate with those with whom you match closely (this feature is not available on the FamilyTreeDNA website, at least not if you do not have a perfect match with anyone as I do).
The Genealogy of Mexico DNA Surname Project enables you to do the DNA test at FamilyTreeDNA at a discount to their standard fees (the 12 marker Y DNA test will cost you USD 99 instead of USD 159).You need to have a Y DNA lineage to Mexico or some US States to be eligible for the discount.
Finally, a few remarks to my previous messages:
In one of my previous notes, I wrote that I had compared my DNA profile (at the www.ysearch.org website) with some other persons who bear the name Leal and that we did not have a positive match.This seems to suggest that not all Leals have a common paternal ancestor.I have been jumping to conclusions:the other Leals did not post their DNA material on the site (!) so nothing was matched apart from our common surname.How stupid of me.
The FamilyTreeDNA website stresses the importance of bearing the same (paternal) surname when matching one’s Y DNA profile:one can only say that two persons have a statistically certain, relatively recent common paternal ancestor if the two match closely and bear the same surname.
Every human being gets her/his DNA material from her/his father and her/his mother (equally distributed).The X and Y DNA are special – among other things - in the sense that (i) the X is passed on from mother to daughters and sons, (ii) the Y from father to sons only, (iii) the two combined determine one’s sex (XX pairing for females and XY paring for males) and (iv) the Y DNA can be used determine deep paternal ancestors.However, I may have the same Y DNA profile (at least the slowly mutating elements) as a paternal ancestor living tens of generations ago, but all his other DNA material will have diluted over time.In other words, I have more (DNA) in common with my mother’s mother than I have with my “deep paternal ancestor.”