Question

50PTS: In the vegetable selection of a grocery store, there are many familiar vegetable, such as Brussels sprouts, cauliflower, broccoli, kale, and kohlrabi. It may be surprising to learn that all these vegetables are varieties of the same species. They are the result of genetic manipulation through a process called artificial selection. Instead of using the latest gene splicing techniques, artificial selection uses selective breeding to select for desired traits. Over 2500 years ago, farmers started keeping Brassica oleracea with traits they desired. They grew these plants and kept the seeds from the most desirable plants. Overtime, after repeating this process, they were able to reliably grow plants with the desired traits. This diagram is a model that shows some of the variations of the wild Brassica oleracea.

1. Explain how selective breeding takes advantage of naturally occurring variation. Use evidence from the passage and the diagram to support your explanation.
2. Describe the DNA in a cauliflower plant is similar to and different from the DNA in Brussels sprouts.
3. Broccoli looks very different from the wild Brassica oleracea. Is broccoli a transgenic plant? Explain your answer.

Answer 1

1. Selective breeding takes advantage of naturally occurring variation by selecting and breeding individuals with desirable traits. In the case of Brassica oleracea, farmers selectively bred plants with larger leaves, flower buds, or stems that eventually led to the development of the different vegetable varieties we have today. The passage explains that farmers kept seeds from the most desirable plants and planted them, which allowed for the desired traits to become more prominent in the next generation. The diagram shows the variations in the wild Brassica oleracea and how they have been selectively bred to produce different vegetable varieties. This process of selective breeding takes advantage of natural genetic variation, allowing for the cultivation of plants with specific traits desired by humans.

2. The DNA in a cauliflower plant is similar to and different from the DNA in Brussels sprouts. Both cauliflower and Brussels sprouts belong to the same species, Brassica oleracea, and therefore share a lot of their DNA. However, each vegetable variety has undergone selective breeding, resulting in differences in their DNA that code for specific traits. For example, the DNA that controls the formation of flower buds in Brussels sprouts may be different from the DNA that controls the formation of the dense flower head in cauliflower. Additionally, the two vegetables may have different versions of genes that control similar traits, resulting in slight genetic differences.

3. Broccoli is not a transgenic plant. Transgenic plants are those that have had their DNA artificially modified by inserting genes from other organisms. Broccoli, along with other Brassica oleracea varieties, was produced through selective breeding, which involves selecting and breeding plants with desirable traits from within the same species. While broccoli looks very different from the wild Brassica oleracea, its genetic makeup is still largely the same as the original plant, with genetic modifications occurring through selective breeding over many generations rather than through artificial gene insertion.