The risky life of my Y-DNA

[geebee]

One thing I never intended to say -- and I don't believe I did -- is that there's something wrong with caring about your Y line. I just don't think it's quite a tragedy when one small part of a much larger group of very similar Y chromosomes is not carried on to the next generation. But, that's just my opinion.

I think we over-estimate how much diversity is present in a human Y chromosome. Just for fun, I used David Pike's tool to "Search for Discordant SNPs in Parent-Child Raw Data Files" with my 23andMe file, and that of an unrelated male. (http://www.math.mun.ca/~dapike/FF23u...ir-discord.php)
I wanted to look at only SNPs on the Y chromosome.

In the other man's file, there were a total of only about 1806 SNPs. All of these should have been present in my file, as well, plus many more. (I'm on both v2/v3, whereas he's on just v3.)

The total number of SNP differences? Seventeen. Only four of these SNPs were in genes; the other thirteen were all intergenic. And we're not even in the same haplogroup. I'm in R-M427, and he's in R-M529 (per 23andMe).

It would be a great exaggeration to say that any two fully functioning Y chromosomes may be pretty close to interchangeable, but even sons who closely resemble their fathers probably don't do so because of anything on the Y chromosome -- apart from the sex-controlling genes, of course, like SRY. Rather they do so because of genes on the autosomes.

Finally, the percentage of your nuclear DNA that the Y chromosome represents? About 1%. The X chromosome represents about 5 times that amount.

[MitchellSince1893]

My y-dna line has been treading on thin ice for at least 5 generations...each generation only having a single male descendant.

[rms2]

Of course, it wouldn't matter if the x chromosome were the size of an elephant. There is no guarantee that the x chromosome passed by a man to his daughter(s) will be passed down to any of his grandchildren or, if it is, that it will be passed down to any succeeding generations. The y chromosome, however, as tiny a percentage of the total dna as it is, goes to each of a man's male line descendants in perpetuity, altered in time by mutations, but not untraceable. That is what makes y-dna so handy for research: it is fairly straightforward and easy to track.

Let's stipulate that every man's y chromosome is mostly like every other man's y chromosome - especially if, for example, an R1 man compares himself to another R1 man. Still, the differences are sufficient that men can be divided into different y-dna haplogroups and subdivided into subclades and into subclades of subclades, etc., with different geographic distributions and different histories.

Besides, it isn't the percentage of total dna or the molecular structure or the number of genes or the number of SNPs that matters when it comes to y-dna. What matters is what it signifies, which is one's unbroken male line of descent, one's historical patrilineal heritage.

I got it from my father, and he from his father before him, and so on, back into the dim twilight of prehistory. Thus the y-dna signifies something far greater than mere biology. It is not itself spiritual, but it represents a spiritual heritage, the unbroken connection to one's fathers. That is what makes y-dna of paramount importance, at least to me.

[geebee]

Of course, it wouldn't matter if the x chromosome were the size of an elephant. There is no guarantee that the x chromosome passed by a man to his daughter(s) will be passed down to any of his grandchildren or, if it is, that it will be passed down to any succeeding generations. The y chromosome, however, as tiny a percentage of the total dna as it is, goes to each of a man's male line descendants in perpetuity, altered in time by mutations, but not untraceable. That is what makes y-dna so handy for research: it is fairly straightforward and easy to track.

Let's stipulate that every man's y chromosome is mostly like every other man's y chromosome - especially if, for example, an R1 man compares himself to another R1 man. Still, the differences are sufficient that men can be divided into different y-dna haplogroups and subdivided into subclades and into subclades of subclades, etc., with different geographic distributions and different histories.

Besides, it isn't the percentage of total dna or the molecular structure or the number of genes or the number of SNPs that matters when it comes to y-dna. What matters is what it signifies, which is one's unbroken male line of descent, one's historical patrilineal heritage.

I got it from my father, and he from his father before him, and so on, back into the dim twilight of prehistory. Thus the y-dna signifies something far greater than mere biology. It is not itself spiritual, but it represents a spiritual heritage, the unbroken connection to one's fathers. That is what makes y-dna of paramount importance, at least to me.

Fair enough.

[RobertCasey]

Finally, the percentage of your nuclear DNA that the Y chromosome represents? About 1%. The X chromosome represents about 5 times that amount.

Unfortunately, the other 99 % of atDNA is recombinational in nature - so its ability to break through most brick walls for me is not present. mtDNA would be another great alternative to YDNA - but it is only 16K base pairs which is not enough content to be very useful compared to 58M base pairs with YDNA. Full Genomes new long read test has now doubled the private YSNP per test by scanning 20M base pairs (twice the amount of Big Y). That is over 1,000 more times content than mtDNA. XDNA is unfortunately 50 % recombinational and 50 % randomly inherited. So it can go back further than atDNA but not significantly.

So basic biology and math just do not show near the long term promise for atDNA and XDNA testing. atDNA remains extremely useful for recent connections and 200 years from now will be very useful to future researchers as well. mtDNA will unfortunately fill the role of second look of mankind from an deep ancestry point of view and some very limited genealogical uses. There is a recent study that stated that YDNA (both YSNPs and YSTRs) would average between 10 to 20 mutations per generation. Unfortunately, sorting out volatile YSTR marker values will require 1000X more YDNA testers. At this resolution, just like atDNA testing, you would have to test multiple male descendants of each of your male ancestors.

[TigerMW]

Unfortunately, the other 99 % of atDNA is recombinational in nature - so its ability to break through most brick walls for me is not present....

I agree, Robert. I've been looking through Family Finder after Family Finder results/matches. I think it is good for the first couple layers of cousins but it is not big help at breaking through brick walls back in time.

It still appears Y DNA has the best ability to break through records into what I'll call pseudo-pedigrees. That sounds bad but it is identifying Most Recent Common Ancestors, the potential surnames, clan affiliations, historical perspectives, etc. I find it fascinating. I don't have to know the guy's name and birth certificate to be able to read about the Norman Conquest of Wales and Norman Conquest of Ireland and figure out where my ancestors were in the mix with fairly decent confidence.

Likewise, some old stories about religious affiliations in Germany and Switzerland as well as political associations in Prague turned to out be very likely and not just old stories.

... and an old story, actually a book, about an ancestor who was a glorified rebel in Scotland with a great escape just doesn't look true. Or at least his affiliation with the Campbell's was on the maternal side if it was. I'm still looking for that great matching Y DNA to see what it is currently surnamed or where it is from.

[rms2]

I agree, Robert. I've been looking through Family Finder after Family Finder results/matches. I think it is good for the first couple layers of cousins but it is not big help at breaking through brick walls back in time.

It still appears Y DNA has the best ability to break through records into what I'll call pseudo-pedigrees. That sounds bad but it is identifying Most Recent Common Ancestors, the potential surnames, clan affiliations, historical perspectives, etc. I find it fascinating. I don't have to know the guy's name and birth certificate to be able to read about the Norman Conquest of Wales and Norman Conquest of Ireland and figure out where my ancestors were in the mix with fairly decent confidence.

Likewise, some old stories about religious affiliations in Germany and Switzerland as well as political associations in Prague turned to out be very likely and not just old stories.

... and an old story, actually a book, about an ancestor who was a glorified rebel in Scotland with a great escape just doesn't look true. Or at least his affiliation with the Campbell's was on the maternal side if it was. I'm still looking for that great matching Y DNA to see what it is currently surnamed or where it is from.

Y-dna is the only thing that has helped me in trying to break through the brick wall in my father line. That may sound obvious because it is my father line after all, but what I mean is that autosomal dna just wouldn't do it, even though I do have a couple of minor matches, one on Family Finder and one on Ancestry DNA, that point that way. It was my y-dna matches that led to the recent breakthroughs I have enjoyed by directing us to Fayette County, Pennsylvania, where I would not have thought to look but which has turned out to be a veritable gold mine of genealogical information.

[Pylsteen]

It goes fast. My grandfather has ca. 20 male cousins, and of his generation there are more than 50 males, going back to one man in 1700. An increase from 1 to 50, which is about ten times the growth of the general population.