转基因是一种现代生物技术，通过将外源基因导入目标生物体中，改变其遗传组成以表达特定的性状或增强某些功能。在转基因领域，标记被广泛应用于监测和确认基因的存在和表达。为什么选择标记作为转基因技术的一部分呢？

首先，标记可以帮助科学家确认外源基因是否已成功导入到目标生物体中。通过添加特定的标记序列，研究人员可以容易地验证转基因生物体是否表达或携带所需的基因。这对于转基因作物的开发尤为重要，因为它们需要确定何时外源基因已经稳定地整合到基因组中。

标记还可以用于确认转基因生物体的后代。当转基因植物繁殖时，标记可以帮助确定哪些植株携带了外源基因，并且基因是否在后代中保持稳定。这对于选择和筛选具有所需性状的转基因品种至关重要。

此外，标记也能够帮助区分转基因和非转基因生物体。在农业领域，转基因作物与传统作物共存是常见的情况。通过使用特定的标记，可以轻松地将转基因作物与传统作物区分开来，确保无意间混入转基因品种的风险减少到最低。

然而，尽管标记在转基因技术中有其重要作用，但也面临一些争议和挑战。一些人担心标记可能对人类健康和环境造成潜在的风险。因此，科学家们一直在努力研发更安全、更精确的标记方法，以减轻这些担忧。

总结而言，选择标记作为转基因技术的一部分具有明显的优势。标记可以帮助确认基因的存在和表达，辅助筛选具有所需性状的转基因品种，并区分转基因作物和传统作物。尽管存在一些争议，但随着科学技术的进步，我们相信未来会有更安全、更高效的标记方法出现。

Translation:

Genetic modification is a modern biotechnology that involves introducing foreign genes into target organisms to alter their genetic composition and express specific traits or enhance certain functions. In the field of genetic engineering, markers are widely used to monitor and confirm the presence and expression of genes. Why are markers chosen as part of genetic modification technology?

Firstly, markers can help scientists confirm whether foreign genes have been successfully introduced into the target organism. By adding specific marker sequences, researchers can easily verify whether the transgenic organism expresses or carries the desired gene. This is particularly important for the development of genetically modified crops, as it is necessary to determine when the foreign gene has been stably integrated into the genome.

Markers can also be used to confirm the offspring of transgenic organisms. When transgenic plants reproduce, markers can help identify which plants carry the foreign genes and whether the genes remain stable in the progeny. This is crucial for selecting and screening transgenic varieties with desired traits.

Furthermore, markers can also help distinguish between transgenic and non-transgenic organisms. In agriculture, coexistence of genetically modified crops and conventional crops is common. By using specific markers, transgenic crops can be easily distinguished from conventional crops, minimizing the risk of unintentional mixing with transgenic varieties.

However, despite the important role of markers in genetic modification technology, they also face some controversies and challenges. Some people are concerned about potential risks to human health and the environment posed by markers. Therefore, scientists have been working on developing safer and more precise marker methods to address these concerns.

In conclusion, choosing markers as part of genetic modification technology has clear advantages. Markers can help confirm the presence and expression of genes, assist in selecting transgenic varieties with desired traits, and differentiate transgenic crops from conventional ones. Although there are some controversies, we believe that with advances in scientific technology, safer and more efficient marker methods will emerge in the future.