Saliva DNA collection cards are convenient and efficient tools for DNA collection, with a wide range of applications in multiple fields.

 Medical Field

1. Disease Diagnosis and Genetic Testing
   • Diagnosis of Monogenic Genetic Diseases
     Many monogenic genetic diseases are caused by mutations in specific genes. Saliva DNA collection cards can be used to collect DNA samples from patients or suspected patients. By performing genetic testing on these samples, the presence of disease – causing gene mutations can be determined. For example, in the diagnosis of cystic fibrosis, the mutations in the CFTR gene can be detected. If a mutation is found, a diagnosis can be made, which helps doctors develop personalized treatment plans for patients.
   • Assessment of Genetic Susceptibility to Complex Diseases
     For complex diseases such as cardiovascular diseases, diabetes, and cancer, genetic factors play a significant role. Using saliva DNA collection cards to collect an individual’s DNA and analyze the gene polymorphisms related to these diseases can assess the individual’s genetic susceptibility to a certain disease. For instance, by detecting mutations or specific genotypes of certain cancer – related genes (such as BRCA1 and BRCA2 in relation to breast cancer), disease risk warnings can be provided to patients, enabling them to take preventive measures such as adjusting their lifestyle and increasing the frequency of disease screening.
   • Research in Pharmacogenomics
     Individual responses to drugs vary, partly due to genetic differences. Saliva DNA collection cards can be used to collect patients’ DNA for analyzing genes related to drug – metabolizing enzymes, drug targets, and drug transporters. During the drug treatment process, based on the genetic test results, doctors can select more appropriate drugs and dosages for patients, achieving personalized medicine. For example, when using warfarin for anticoagulant treatment, detecting the polymorphisms of CYP2C9 and VKORC1 genes helps determine the appropriate warfarin dosage, improving the safety and effectiveness of drug treatment.
2. Oral Medicine Research and Disease Diagnosis
   • Oral Microbiome Research
     Saliva contains a rich microbial community, which is closely related to oral health and diseases. By collecting saliva samples with saliva DNA collection cards, the microbial DNA in the saliva can be analyzed to study the types, quantities, and diversity of oral microorganisms. For example, in the research on the pathogenesis of dental caries and periodontitis, the changes in the oral microbial community can be understood by detecting the bacterial DNA in saliva, providing a basis for the prevention and treatment of oral diseases.
   • Diagnosis and Research of Oral Cancer
     Saliva DNA collection cards can be used for the early detection and diagnosis of oral cancer. Oral cancer cells release DNA fragments into saliva, and by detecting these free – floating DNAs, oral – cancer – related gene mutations can be identified, providing a non – invasive method for the early screening of oral cancer. In addition, during the follow – up after oral cancer treatment, saliva can also be collected to monitor the recurrence of the tumor.

II. Forensic Science Field

1. Individual Identification
   • Crime Scene Investigation
     In criminal cases, the crime scene may contain the suspect’s saliva, such as on cigarette butts, bite marks, water cups, etc. Forensic scientists can use saliva DNA collection cards to collect these saliva samples, extract the DNA, and compare it with the DNA of suspects or that in the database, thus determining the identity of the suspect. This method plays a crucial role in solving cases such as rape and robbery.
   • Identity Identification in Disaster Incidents
     After large – scale disasters (such as earthquakes, fires, and plane crashes), the bodies of the victims may be severely damaged, making it difficult to identify them through traditional methods. If saliva – containing items from the victims’ belongings or the scene can be found, saliva DNA can be collected using saliva DNA collection cards and compared with the DNA samples provided by the families, which can help determine the identity of the victims, comfort the families, and facilitate the subsequent handling of the disaster.
2. Paternity Testing
   In cases involving disputes over parent – child relationships, saliva DNA collection cards provide a simple and painless way to collect DNA. Saliva samples from parents and children can be collected separately. By analyzing the DNA in the samples, detecting specific genetic markers (such as short tandem repeat sequences, STRs), and calculating the probability of the parent – child relationship, it can be determined whether the parent – child relationship is established. This method is an important source of evidence in resolving civil cases such as custody disputes and inheritance disputes.

III. Genetic Research and Bioinformatics Field

1. Population Genetics Research
   Studying the genetic structure and genetic diversity of different populations is an important part of population genetics. Saliva DNA collection cards can conveniently collect DNA samples from a large number of people, which are used to analyze phenomena such as gene frequencies, genotype frequencies, and genetic drift in the population. For example, when studying the genetic differences among different ethnic groups or geographical populations, gene typing of the collected saliva DNA samples can reveal the genetic relationships and migration history among populations.
2. Research on Gene Expression and Function
   In basic biological research, scientists need to study the expression and function of genes. Saliva contains various cell types, including oral epithelial cells and immune cells, and the gene expression in these cells can reflect the physiological and pathological states of the body. By collecting saliva samples with saliva DNA collection cards and extracting the RNA in them, the expression patterns and functions of genes in the oral cavity or the whole body system can be studied. For example, when studying the gene expression changes during the oral inflammatory response, saliva RNA can serve as an important research material.
3. Construction of Bioinformatics Databases
   To better understand the relationship between the human genome and diseases, the construction of large – scale bioinformatics databases is required. The large number of DNA samples collected by saliva DNA collection cards can provide rich data resources for the databases. These data include information such as gene sequences, gene variations, and gene expressions, which help researchers discover new associations between genes and diseases through data mining and analysis, promoting the development of biomedical research.