# From Biological Gene to Functional Gene: Revolutionizing Product Innovation Design
## 3 Theory Research on Functional Gene
### Characteristics of Functional Genes  
The concept of functional genes is derived from the inspiration of biological genes, and therefore, functional genes possess similar characteristics to biological genes. However, due to the differences between engineering systems and biological systems, functional genes themselves have distinct features. Biological genes exhibit heritability, determinants of trait development, and plasticity [55]. Building upon these foundations, scholars have summarized the characteristics of functional genes from the perspectives of extraction, storage, expression, variation, screening, and other aspects, as shown in Figure 4.  
Independence: The premise of functional gene extraction. [PERSON] et al. [56] utilized NLP algorithms to extract patent functional information as knowledge modules for retrieval. Genes are the smallest genetic units, and the independence of functional genes implies that they can exist independently without mutual dependence. This ensures that functional genes can be extracted, stored, and called independently, making them the minimum knowledge units that can be recorded for functional genes. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
\begin{tabular}{c} \(\surd\): Includes this phase of research. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._Stability: The foundation of functional gene storage. [PERSON] et al. [57] proposed that in order to achieve industrial digitization and improve design efficiency, design knowledge would be stored in external devices such as computers and cloud storage. As the carrier of design knowledge, functional genes need to remain unchanged despite variations in time, environment, and other factors, ensuring the stability of the stored design knowledge. Heredity: The core of functional gene expression. [PERSON] et al. [58] extracted design knowledge from existing systems and documents, providing a foundation for knowledge reuse and achieving intergenerational inheritance of design knowledge. [PERSON] et al. [59], using gas turbines as an example, conducted topological optimization based on existing design resources, achieving intergenerational inheritance of design features. As the carrier of design knowledge, functional genes exhibit genetic characteristics inherited from the source systems of the knowledge. This is manifested in the partial inheritance of the functionality and structure of the original system in the design of new products. Plasticity: The guarantee of functional gene innovation. [PERSON] et al. [60] extracted design knowledge from a case database and made changes to physical attributes, positions, and other parameters based on the target system. In the process of reusing functional genes, directly using existing functional genes often fails to meet the predetermined design requirements of the target system. By utilizing gene manipulation techniques such as decomposition and recombination, functional genes can be transformed and optimized, leading to the generation of systems with new functionalities. Adaptability: The selection of functional gene screening. [PERSON] et al. [61] proposed that the trial-and-error method in design consumes a significant amount of resources, and screening design knowledge can help reduce the number of product iterations. The adaptability of functional genes is reflected in two aspects. Firstly, in the selection of functional genes, beneficial gene variations that meet user requirements will be retained, while variations that do not fulfill these requirements will be eliminated. Secondly, in the selection of functional gene sets, there is a coupling relationship between functional genes, which can result in defects in the functional gene set. Functional gene characteristics determine their effective application in product design. Among them, independence and stability determine the feasibility of gene storage.