Humans eat different types of vegetables each and every day but never know about their origin. They have no idea which vegetables belong to which plant species, but the human mind has always one theory, i.e. each and every vegetable has different plant species and their origin. But it is always possible that different vegetables can have origin from the same plant species.
According to Business Insider, there are many vegetables which the humans have might eaten, or they eat regularly and they are derived from the same plant species, that is Brassica Oleracea. From the last few thousand decades, Brassica Oleracea has been bred into subspecies, which gave origin to different types of veggies, which are included in the human diet list now.
Brassica is also known popularly as the wild mustard plant. "The wild plant is a weedy little herb that prefers to grow on limestone outcroppings all around the coastal Mediterranean region," a researcher Jeanne Osnas from Purdue University said. She also has a blog called 'The Botanist in the Kitchen', where she mentioned about the same plant species Brassica Oleracea.
AOL reported that there are mainly 6 common vegetables which the human eats regularly and they are a part of the same plant species, Brassica Oleracea. These vegetables are Brussels sprouts, Broccoli, Cabbage, Cauliflower, Kale, and Kohlrabi. Brassica Oleracea was being bred for over hundreds of years for creating dozens of different vegetables.
Kale was created by making the plant's leaves bigger, which was being domesticated in Europe during the year 300 BCE. Cabbage was created by the selection of large terminal bud around the year 1200. Brussels sprouts were being created with the help of grown buds along the plant stem. Broccoli was created by the selection of large flower clusters. With the help of above examples, it can easily guess that the same plant species was used to tinker with the genetics of the foods, since a very long time, which is now called genetically modified foods, with new lab technologies and procedures.