Hmm, lively debate we have going on here but let's keep it nice.
In addition to new plants, human beings have also created new types of dogs and cats via selective breeding. The following is an excerpt from the PBS series, Dogs That Changed the World.
'...according to genetics, all dogs evolved from the savage and wild wolf — in a transformation that occurred just 15,000 years ago.'
'Most of these breeds exploded onto the scene over the past 150 years, spurred by the Victorian-era passion for the “dog fancy” — the selective breeding of dogs to enhance particular characteristics. By tinkering with its genetics, humans made the dog the most varied animal species on the planet — and also created a host of hereditary health problems.'
Again, if this can be done to plants and animals, why not human beings? The creation of different types of dog (cat) breeds is no different than what the NOI says that the scientist, Yakub, did but with human beings! According to NOI teachings, it took 600 years of selective breeding (and tinkering with genetics) to create the first Caucasian.
To expect white historians and scientists to look closely into what the NOI has proclaimed to sincerely check its validity is to be naive. We are living in the world of white supremacy. The entire system is built on the premise that whites are superior to everyone else. Acknowledging or even seriously considering the possibility that a group of people (whom they despise) is responsible for their very existence would destroy the entire system of white supremacy. It is much safer and more pleasant to hold onto the Swiss cheese theory that whites became white by simply migrating to northern latitudes.
Here is a fact sheet on Vitamin D from the NIH. You can skip to the section on 'Groups at Risk of Vitamin D Inadequacy.'
Finally, I found this article via an internet search. I believe it answers some of the questions raised in this thread.