Genetics Study Notes

Genetics Overview

  • Completed Human Genome Project in 2003.
  • Most diseases have genetic components.
  • Studies human genes, their interactions, and environmental factors.

Genetic Basics

  • DNA is key; involves cell division, chromosomal alterations, gene expression, mutations, and diseases.
  • Human cells contain 46 chromosomes; sex chromosomes determine male (XY) or female (XX).

Cell Division

  • Mitosis: Produces 2 identical daughter cells.
  • Meiosis: Forms sperm and ova.

Chromosomal Alterations

  • Zygote can be monosomic or trisomic.
  • Examples: Trisomy 13 (Patau syndrome) and Trisomy 18 (Edwards syndrome).
  • Chromosomal alterations include inversions, deletions, and duplications.
  • XY chromosome characteristics: Y has few genes; X has many critical genes.

Genes

  • Genes encode proteins for various physiological functions.
  • Genotype: an individual's set of genes.
  • Phenotype: observable physical or biochemical characteristics influenced by genotype and environmental factors.

Mutations and Disease

  • Mutations can be inherited or acquired, affecting health.
  • Single-gene mutations lead to over 5000 hereditary diseases (e.g., cystic fibrosis).
  • Trinucleotide repeat disorders (e.g., fragile X syndrome) are significant.

Inheritance Patterns

  • Almost all genes pair; one gene from each parent is transmitted.
  • Dominant disorders: one altered gene causes disease.
  • Recessive disorders: both alleles altered; traits often affect males and females equally.

Genetic & Family History

  • Important for identifying risk factors; includes medical conditions and ancestry.

Genetic Testing

  • Screening tests identify individuals at risk.
  • Diagnostic tests confirm diagnoses.
  • Prenatal testing available for all women under 20 weeks of care.

Ethical, Legal, and Social Implications

  • Genetic testing must be voluntary; discuss risks and benefits.
  • Consider potential discrimination and privacy concerns related to genetic information.
  • Health Insurance Portability and Accountability Act (HIPAA) protects against discrimination based on genetic information.