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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.