|Banana Evolution |
The Evolution of the Banana
Some bananas plants have evolved from wild seed filled bananas to the now commonly recognized edible diploids. Note: There are still many hundreds of banana varieties which still propagate by seeds.
The origin of the domestication and cross breeding for seedless bananas is unknown - if it ever existed at all.
It is generally assumed that this cross breeding and nurturing process most likely started with farmers (?) transplanting the offshoots (commonly known as suckers or shoots) of plants that were more favourable by virtue of having less or smaller seeds and more fruit. And yes, that is an oxymoron because if the banana plant was producing suckers in the first place, then they were well on their way to asexual reproduction.
It is also possible - and more likely - that some of the banana plants simply evolved this way on their own accord especially given the massive amount of time it would have taken for seedless bananas to evolve.
The futility of short sighted manipulations
An example of time scale showing how potentially futile this "Farmer" manipulation theory is shown in the following experiment conducted on mice over a 20 year period. (CSIRO)
Lamarckism The Great Mutilation Experiment:
In 1891, a scientist by the name of August Friedrich Weismann conducted an interesting but cruel experiment with mice where by he was trying to prove a theory called "Lamarckism" which teaches "inheritance of acquired characteristics."
The theory basically states that birds living in the water grow webbed feet, giraffes have long necks because they eat leaves from trees etc
Weismann started cutting the tails off mice for just 19 generations (1 year 8 months) to try and prove that the theory of Lamarckism was correct.
Unfortunately for Weismann, he was proven wrong with zero net result in his favour.
Around 60-70 years later, the Australian CSIRO conducted a similar experiment of cutting the tails off mice for 20 years and, given that mice can reproduce at 35 days of age, this means that you should get over 200 generations of mice within that 20 year period. The net result was that after 20 years, there was no change in the length of the tails of the mice that were allowed to keep their tails at the end of the experiment.
However, this "Lamarckistic mice experiment" lacked one major component and that was environmental causality. This "environmental causality" is also very important for the evolution of our beloved bananas.
In other words, if the mice had some kind of extreme repetitious localised problem - such as the ends of their tails being burnt daily for 20 years plus - this would cause or trigger an epigenetic evolution stimulated from within the mice themselves to reduce the tail size.
So while the simple action of cutting off the tail was initially painful, it was a short lived pain which did not overly affect the mouse after the wound had healed.
So, if environmental causality (external stimulus) is the cornerstone of natural epigenetic evolution, then one may assume that a decline in, or lack of pollinators such as bees (for example), may have been the catalyst for the seedless varieties to start their own independent evolution, especially when you consider the major meteorite hypothesis which claims that a major meteorite hits this planet every 500 - 600 years or so.
Back to the theory that humans genetically farmed seedless bananas.
When you consider the times (several thousand years ago at least) and the distances involved, plus the lack of financial motivation given that so many bananas grew wild anyway, 200 or more generations of people focused on consciously growing anything with an pre-conceived and unproven "idea" as an outcome, it is extremely hard to imagine given that droughts, pestilences, plagues, famine, pilfering by animals and other people, and even wars or blood feud clashes which the average person would have had to contend with - often multiple times within their own lifetime.
*** Please Note that this is the short version on multiple fronts regarding this discussion including that the Jews and a surprising number of other indigenous peoples, tribes and religions have been circumcising males for at least 4,000 years with no visible physical changes being noted. This includes some Aborigine tribes.
Anyone who has ever been to remote jungle locations within SE Asia, India, Africa or Central America will have noticed that "generally speaking" the native peoples do not commercially grow food crops such as bananas per se and tend to be more focused on growing ground crops and the "Hunter Gatherer" type of existence.
And given the simple fact that the bananas developed "suckers" in the first place shows that the evolution of some seedless banana plants may have been a natural one.
Seed bearing Banana plants that were still "sexually active" (requiring both male and female to procreate) continued cross breeding with other fertile banana plants and as such, these formed the Musa acuminata subspecies or Musa balbisiana species.
Under the nomenclature system, those cross-pollinating events became the foundation of the AA and AB genome groups, the letter A standing in for acuminata and B for balbisiana.
From Diploids to Triploids
Some bananas went on to produce triploid plants when one of the diploid parents normally passed on one copy of its genome, while the other contributed both copies (a phenomenon called meiotic restitution). This process produced three main genome groups : AAA, AAB and ABB.
Just be Happy
However bananas evolved, just be happy that they did because they bring joy to hundreds of millions of people every year.