i here you brick and i understood your point from the beginning. just as you listed the geneology of jack herer with all the selections over thousands of years i find it hard to believe any seed companies statement of a 100% sativa to be outlandish outside of pure landrace strains of course. it's been far to much natural selection along with man tampering to think like that in my opinion.
I can see your point and accept the possibility but you do also have to factor in probability. Due to the geographic isolation of some regions of the world where only sativas or only indicas grew while there may have been some natural cross breeding of strains they would for many, many, many throusand of years have had to have still remained all sativa or all indica since the other was just not there to be crossed with the one either naturally, accidentally or intentionally.
When my brother in law was returning from Vietnam he packed two very large stereo speakers with herb and also a large bag of seeds from the Da-Lat region which produced the strain that came to be known as Dalat. The farmer he got it from said his father and his grandfather and other family members before them had all grown the same strain. The geographic isolation of the area pretty much assured that if there had ever been any crossing is was totally unintentional and that it would have had to have been another sativa so while possibly not pure as in never been crossed it would still be pure as in pure sativa, totally lacking in any indica influence/crossing.
Then you have to consider how many of the strains in the breeding stables of some breeders, mainly those who have been breeding far longer than others, have such strains, strains that were obtained by getting them from people who like my brother in law at some point brought pure strains from one region of the world to another and who did not cross them with anything else or if they did only bred them with other pure strains.
If you think back to the work of the Haze Brothers they worked with pure sativa strains. They, and others like them, were doing their thing well before 'The Dutch Masters' and a fair number of strains 'The Dutch Masters' started out with were the work of others who only or mainly worked with pure strains but who even if they made crosses kept the original pure strains in their stable still in their pure form.
Consider the roots of the real true original strain that came to be known to the world as Romulan. It was a tall lanky long flowering Korean strain that was brought back to Canada by Canadian soldiers who returned from the Korean War. They worked to acclimatize it to their region and over many years kept picking the faster flowering shorter bushier (even if only slightly so) phenotypes from their crops and bred them together until over time what began as a tall lanky long flowering strain had turned into a short bushy short flowering strain.
Some did cross breed with indicas but according to Romulan Joe the alteration in the high was not something most liked so that was usually abandoned and then cross breeding with other sativa strains was tried, and in some cases liked and crossbreeds did spread, but the original shortened quicker flowering genetics were always preserved. Later when 'The Dutch Masters' got their hands on the strain they did make crosses with indicas but regardless of it's physical appearance and flowering time no one who has ever smoked the true original Romulan can deny it's true lineage. Only the later crosses, some that were not sold as being crosses and still called Romulan were different and had a strong indica influence.
In some cases because regions were not so geographically isolated there were without doubt the crossing of sativa and indica strains long, long, long before even the earliest of what could be called modern day breeders came along. Seeds and cannabis plant matter found in the oldest archeological digs in Pakistan and Afghanistan have found that at that time sativa strains were native to the area and other digs that do not date back as far in time show that indica strains from far Western China had moved into the area, either by man or animal or both, and over time crosses, either unintentional ones made in nature or possibly ones made by man, caused indica strains to be the predominant strains of the region. But that might mean that by the time seeds began to spread around the world with travelers and traders and what could be called the first of the modern day breeders came to be that there were no 100% pure indica strains in either Afghanistan or Pakistan and they were only believed to be pure indica and have until this day been claimed to be pure indica.
What it all comes down to is what each breeder has in their breeding stable. Some have strains that go back many, many decades and that came from geographically isolated regions. They very well might have strains that are 100% sativa or 100% indica, mainly the older longer in the tooth breeders though would be the most likely to have them and more recent breeders would be more likely to have stables made up of at best early crosses, still possibly all sativa or all indica, but mainly crosses of sativa and indica that they can work with.
While I would not claim to be actual friends or pals with any breeders I have exchanged a good number of messages and PMs and in the early days of online sales I have spoken to several on the telephone when asking information to make strain selections and what I was in some cases told was some breeders of the time would have say a pure female Panama Red or Malawi Gold or Durban Poison or whatever, but not a male, or it might have been the other way around. Another breeder or breeders would have the opposite but none were eager to share or trade so they could only use what they had in crosses. Others though had both males and females and did, and supposedly do until this day still have both in their breeding stables, there there are not many of them that are so lucky.
Most modern claimed to be pure sativas I have grown, mostly ones that carried the names of famous pure sativas of the past, did not at all come close in growth, physical appearance or high to the strains of the same name I smoked in the 60's and 70's so in those cases I do not for one second believe them to be pure using any chosen definition of the word. Others, like those I listed which I have grown most of, I do believe to be pure, I do believe to be the Real McCoy. They were a true blast from the past, a trip back in time in Mr. Peabody's Wayback Machine to the 60's and 70's when purity not only did still exist but was the norm.
For those who experienced strains from that era, if they ever run across one today they recognize/remember the high and know if it is the real deal or not. Those who were lucky enough to ever smoke 'the jungle kind' do not forget what it was like any more than they forget their first romp in the sack, or maybe in the backseat of their father's Oldsmobile, and if they are lucky enough to come across it again they know it when they toke it.