What is a primary characteristic of transgenic organisms?

Transgenic organisms are defined primarily by their genetic modification involving the incorporation of DNA from different species. This characteristic allows them to express traits that are not typically found in their natural counterparts, which can lead to benefits such as increased resistance to pests or enhanced nutritional content. For instance, in agriculture, transgenic crops may be engineered to withstand herbicides or to provide higher yields, illustrating the practical application of cross-species genetic material.

The other options do not accurately represent transgenic organisms. They do not exist only in nature, as they are specifically created through biotechnological methods. Transgenic organisms are indeed genetically modified, which directly contradicts the idea presented in one option. Additionally, the ability to reproduce is generally retained in most transgenic organisms, meaning that they can produce viable offspring that may also possess the transgene.