i guess at some level, these graphs show just how easy it would be to create a breed from just a few animals and that there is enough diversity in some breeds to have variability to make classifications and if held long enough that they would become breeds with whatever pressure there was. i guess at some level, that's what breeders do and to me, the concept of breed is meaningless. they are just lineages that have some constraint that narrows the breeding population. guarantee of pedigree is more important. at some point soon, packers will demand it or dock you considerably, which they sort of do now with the black hair coat/polled genes, but will do more of soon.
all cattle are from the same source, auroch's, unless there's something else, so to me, everything is essentially a land race, with some mixing as travel became easier. at least to me, remember, the spotted or piebald pattern was supposedly used to identify the first domesticated livestock and supposedly sort of a brand. then, further stuff happened as the ocean raised, people killing each other, not mixing, then mixing, various reasons populations were in isolation, then mixed. think of the breed registry purity arguments back then. sorry, after reading about this, i am referring to S3. to me, S2 is just the big bang and doesn't really mean what came from what. i could be wrong. but yeah it looks like shorthorn, angus and red angus were from a line and split, obviously one split "earlier" than the other. i guess it would be interesting to draw a graph to see how many animals it took from two breeds the snps in common, regardless of the occurrence, which is sort of what these graphs do, but it would be nice to see just what those numbers are and really see the variability within and between "breeds". for some reason, we tend to weigh heavily a low number of traits to describe breeds or each other and stereotype each other. it can be rather annoying. i guess i would rather focus on major fault (to me genes) such as carrot teats, sloped hips, sickle hock, cow hock, seedy toe, hair type and number and length, fly resistance and make new "breeds" and not worry so much about useless hid color and polled genes. shaver in canada, the santa gertrudis and other REAL breeders to me are the one's who are truly creative and breeders, instead of preservers, who are incredibly useful as well. other "breeders" are useful as well that like to impose pressure on a couple of traits, and then close breed. these guys find the defects, a service to everyone.
http://www.buckmanager.com/2007/07/17/piebald-deer-what-are-they/
oversimplified, but the dendogram just shows relatedness using the markers they used and differences are due to mutations and drift. the more markers in common, the more related they are. has nothing to do with nothing else. i used these a lot in plant breeding and marker searches in row crops early in life.
to me, drifting away isn't really descriptive of the process, they just differentiated differently for whatever reason, including environment latitude, mutation from viruses, bacteria load, flies, migration impulse, from gamma rays, who knows.
my former boss had an office near a guy in this reference. a lot of recent interesting debate arose from this work with respect to humans, which one could imagine could get controversial. drift is obviously dangerous unless one has something in mind and even then, not having enough numbers can still cause problems. cattle breeders in the 1800's seemed to do a better job than those in the 1900's, maybe just because they essentially created most of the breeds and it was easier rather than following and maintaining the mythology.
http://en.wikipedia.org/wiki/Genetic_distance
