In-Depth Notes on Personal Genomics and Genetic Testing

Introduction to Personal Genomics

• Focus on understanding types of genetic testing and the role of Single Nucleotide Polymorphisms (SNPs).
• Learning Goals:
  • Identify types of genetic testing.
  • Describe how SNPs are utilized in genetic testing.

Definition of Genetic Testing

• Genetic Testing: Medical tests identifying changes in chromosomes, genes, proteins.
  • Important for diagnosing genetic conditions or assessing risk for genetic disorders.
• Over 1,000 genetic tests are in development.

Types of Genetic Testing

1. Molecular Genetic Tests:
   • Analyze single genes or short lengths of DNA to identify mutations.
2. Chromosomal Genetic Tests:
   • Examine entire chromosomes for genetic abnormalities.
3. Biochemical Genetic Tests:
   • Assess protein activity levels to identify mutations impacting function.

Specific Testing Methods

• Newborn Screening:
  • Tests for conditions like phenylketonuria and congenital hypothyroidism.
• Diagnostic Testing:
  • Identifies or rules out specific genetic conditions.
• Carrier Testing:
  • Detects individuals carrying gene mutations; relevant for familial planning.
• Prenatal Testing:
  • Identifies genetic changes in a fetus before birth.
• Pre-implantation Testing:
  • Reduces risk of genetic disorders in IVF cases.
• Forensic Testing:
  • Identifies individuals for legal purposes (e.g., paternity tests).
• Direct-to-Consumer Genetic Testing:
  • Companies like 23andMe, Family Tree DNA provide genetic information without a doctor.

Use of SNPs in Genetic Testing

• SNP Definition:
  • Single Nucleotide Polymorphism; variation in a single base in DNA.
  • Example: A change from cytosine (C) to adenine (A) results in a polymorphism.
• SNPs help to investigate ancestry and carrier status for diseases.
• Ancestral Origins:
  • Tests trace lineage through mitochondrial DNA and haplogroups (e.g., Family Tree DNA).

Applications of Genetic Data

• Carrier Testing Applications:
  • Assessing carrier status for certain diseases (42 conditions tracked).
• Genetic Health Risk Reports:
  • Analyze risks for diseases like Alzheimer's and Parkinson's.

Regulatory Considerations

• FDA Concerns:
  • Focused on the analytical and clinical validity of genetic tests.
  • Ensured safety and effectiveness in tests provided by companies like 23andMe.

Complex Genetic Interactions

• Molecular Mechanisms:
  • Importance of recombination events during meiosis in generating genetic variation.
• Example Study:
  • Yeast study examining crossover events and the resultant variations in chromosomes.

Implications of Family History

• Combining SNP data with family medical history provides enhanced predictive power about disease risk.
• Comparison Study:
  • Analyzed the effectiveness of family history versus SNP-based risk prediction models.
  • Speed and efficiency in predicting disease based on genetic predisposition.

Conclusion

• Continued exploration of personal genomics enhances understanding of genetic conditions, ancestry, and risk assessment for diseases.
• Awareness of limitations and benefits important for informed decisions related to genetic testing.