Interesting new genetic info.

Bill from WA · Postby **Bill from WA** » Mon Mar 28, 2005 4:14 pm

http://www.nature.com/ng/journal/v36/n4/abs/ng1326.html

Bill

henthorn · Postby **henthorn** » Mon Mar 28, 2005 8:33 pm

I'm not sure I understood the lingo, but makes me want to learn more.

Nessa · Postby **Nessa** » Mon Mar 28, 2005 8:42 pm

I'm not at all surprised at this Bill. How many breeds are predicated on a single stallion? The Morgan, Shagya Arab, American Standardbred and many others all lead pretty much lead back to a single phenotypically dominate stallion. There are many breeds that have the same problem as the Thoroughbred that only a few sirelines are represented in the breed. I don't know how they will address the problem. What would the solution be?

mary syers · Postby **mary syers** » Mon Mar 28, 2005 9:14 pm

You know this says that across breeds, the non-coding region(makes no genes--we call it nonsense DNA) of the Y chromosome is identical--no diversity. That is amazing, but maybe consistent with the fact that Morgan, QH, TB and those breeds that desend from them are all tail male to the limited Arab imports available in a time frame from the 1600's to the 1800's. If you study Arab pedigrees, you find a similar bias, so maybe the genetic bottleneck is Arabian transposed on it's decendent breeds of horses. Mary

sulphurfire · Postby **sulphurfire** » Tue Mar 29, 2005 5:32 am

Okay will one of ya'll please define, patrilinear, that word is totally unfamiliar to me. Thanks

Bill from WA · Postby **Bill from WA** » Tue Mar 29, 2005 8:16 am

Male line.

madelyn · Postby **madelyn** » Tue Mar 29, 2005 8:32 am

Well isn't that what we all do? Folks send 400 mares to one stallion? Folks patronize a particular sire line? Why would we then be surprised that the X-strands of DNA are diverse while the Y strands are not?

sulphurfire · Postby **sulphurfire** » Tue Mar 29, 2005 8:53 am

Thanks Bill, I suspected but had never run across that particular word before.

WarHorse · Postby **WarHorse** » Tue Mar 29, 2005 8:54 am

From what I understand, the Y strand is non-recombinant. If you pull a 10,000 year old frozen horse carcass out of a bog in Siberia, it will (likely) have the same Y. In humans there are, I believe, four Y strands. That is why genetic geneology can use either YDNA or mDNA.

Pan Zareta · Postby **Pan Zareta** » Tue Mar 29, 2005 9:18 am

The non-recombinant DNA on the Y chromosome is the only unique constant common to ALL members of a sire line. The most important of the genes controlled by that yDNA are those responsible for turning the fetus - which is female by default - into a male. If the yDNA of the founding sires of the breed was identical, then the presuppositions about and mythology of the three founder sire lines are essentially meaningless constructs, at least from the standpoint of contemporary TB genetics.

I find this rather ironic given the historic bias in favor of focusing primarily on the sires' influence in TB breeding practices.

Bill from WA · Postby **Bill from WA** » Tue Mar 29, 2005 9:43 am

Pan Zareta

Exactly my take on things. I have long been of the opinion (even before the advent of DNA studies) that the female was the more pertinent influence in the breeding shed. Initially this was just a gut feeling based on my own research, which was fortified by my examination of scientific breakthroughs over the years. The diverse influences that I believed were transmitted through the female, were what led me to the creation of the Modern Conduit Mare application. Who knows what the future will bring as more studies are brought to light. Exciting stuff.

Bill

Pan Zareta · Postby **Pan Zareta** » Tue Mar 29, 2005 2:37 pm

Bill from WA wrote:Pan Zareta

Exactly my take on things. I have long been of the opinion (even before the advent of DNA studies) that the female was the more pertinent influence in the breeding shed. Initially this was just a gut feeling based on my own research, which was fortified by my aexamination of scientific breakthroughs over the years. The diverse influences that I believed were transmitted through the female, were what led me to the creation of the Modern Conduit Mare application. Who knows what the future will bring as more studies are brought to light. Exciting stuff.

Bill

I'm waiting impatiently for LB's study on the American FF's and for additional work on the English FF's as well. The study published in Animal Genetics '02 revealed very early divergence among the dam lines. Family 10 (haplotype A) for instance, has little in common w/ any of the other families/haplotypes represented in the study. Since only one representative of this family was included in the study it's impossible to say with conviction that her haplotype is likely representative of the Oysterfoot mare. But it's certainly evidence of striking diversity between contemporary producing damlines.

PZ

petersd · Postby **petersd** » Tue Mar 29, 2005 3:28 pm

Uh - I was a history major...

Pan Zareta · Postby **Pan Zareta** » Tue Mar 29, 2005 7:10 pm

petersd wrote:Uh - I was a history major...

Me too (well, Art History was one of my majors...).

Questions?

mary syers · Postby **mary syers** » Tue Mar 29, 2005 9:41 pm

All this diversity in the FF, even before you mention mtDNA, which is almost exclusively a female genetic component. I always thought someone should study the D-loop of the mtDNA for length and diversity between successful TB female families and the run of the mill mare. D-loop length is intimately involved in replication time and number of mtDNA loops in a mitochondria. Amount of mtDNA has a coorelation in humans, anyway on mitochondrial function. This is due to the tendency of mtDNA replication to slip and produce deleted mtDNA--missing genes. Difficult to do and totally ignored in TB. Mary