DNA Tests for Genealogy Purposes

I think there is a lot of confusion here about DNA, how it's tested, and how to interpret our results. I hope that the below will clear up some confusions...

There are four (4) types of DNA in humans that are used for molecular genealogy:

1) Autosomal DNA - inherited from both MOTHER & FATHER (we inherit 50% from mom/50% from dad)

2) X-chromosome DNA - determines gender; whether we are female (XX) or male (XY), females pass on their X chromosome to ALL children, fathers pass on their X
chromosome to their DAUGHTERS only and their Y chromosomes to their SONS only. X-chromosome DNA changes rapidly from generation-to-generation, and so it is not very useful for deep ancestry research

3) Y-chromosome DNA - only men have this and because men only have 1 Y-chromosome, it passes unchanged from FATHER-to-SON over many generations going back deep into one's ancestry on DIRECT male line

4) Mitochondrial DNA - both men and women have this, but only a MOTHER can pass it on to her SONS and DAUGHTERS; it passes from generation-to-generation unchanged for thousands of years (deep-deep ancestry on DIRECT female line)

A man can be haplotype R1b (European), but still be 30% native-American, African, Asian, whatever. In this case, we only tested his Y-chromosome and results prove that his direct PATERNAL line has European origins. Now, if he tests his Mitochondrial DNA (mtDNA), he can also have a European result, but at the same time be 30% Native-American, African, Asian...whatever. We only tested his MATERNAL line

In order to get one's complete ethnic origin breakdown, one needs to get an AUTOSOMAL DNA analysis. This test takes a different strand of human DNA (NOT related to yDNA or mtDNA), that is passed on randomly from BOTH mother and father to each child. We get 50% from mother and 50% from father. Our mother got 50% from her mother and 50% from her father...and our father got 50% from his father & 50% from his mother...etc, etc...all the way up our family tree. It is a complete genetic record.

I think that as more and more NR members get tested, we will learn that we who descend from the founding families of Jalisco, Zacatecas & Aguascalientes are not 100% pure Spanish/Portuguese/Italian/French . We are all a mixture of the three major ethnic groups who populated the region and who comprise our ancestry: European, Native American and African. This is being proven by DNA test results every day.