Genetics and Pharmacogenetics Overview

Chapter 11 Objectives

• Discuss family history as a predictor of disease risk.
• Identify appropriate uses for DNA testing, and explain how such tests might lead to genetic discrimination.
• Define genetic engineering, and explain why cloning and stem cell research are controversial issues.
• Explain three possible remedies for couples experiencing infertility problems.
• List those laws affecting healthcare that pertain especially to children's rights.

Vocabulary

• Heredity: The process by which genetic traits are passed from one generation to the next.
• Genetics: The science that explains the differences and similarities among people and other organisms.
• DNA: Deoxyribonucleic acid, the molecule that makes up chromosomes.

Figure 11.1

• Cell nucleus contains 23 pairs of chromosomes.
• Chromosomes are composed of DNA strands.
• DNA strands are made up of bases.
• Genes are segments of DNA.

DNA

• The relationship between DNA inherited from ancestors and diseases is scientifically confirmed.
• Family history is a significant risk factor for common diseases like cancer, cardiovascular disease, diabetes, autoimmune disorders, and psychiatric illnesses.
• Cultural and socioeconomic factors also influence health risks.

DNA Continued

• Human cells (except egg and sperm cells) contain 46 chromosomes (23 pairs).
• Chromosomes carry genes responsible for various human characteristics (eye, skin, hair color, height, etc.).
• The human genome includes all genetic information needed to create a human being.

The Human Genome Project

• Initiated in 1990 by the U.S. government to analyze the human genome.
• Scientists mapped all genes within the 23 pairs of human chromosomes.
• Completion was in mid-2000, ahead of schedule.
• The actual number of human genes was found to be approximately 20,000 to 25,000, not 100,000 as initially thought.

Testing DNA

• Predictive testing: Identifies genes associated with hereditary diseases to determine disease risk. (e.g., Huntington's disease, Alzheimer's disease).
• Carrier testing: Determines if individuals carry harmful genes that can be passed on to offspring.

More Testing

• Prenatal testing: Used to identify genetic disorders in utero, such as ultrasound and amniocentesis.
• Preimplantation testing: Screens embryos for harmful genes before implantation.

And More Testing

• Forensic testing: Used in law enforcement to analyze DNA samples for criminal investigations.
• Tracing lineage: Determines parentage relationships.
• Newborn screening: Checks for treatable genetic conditions in newborns.
• Diagnostic testing: Confirms diagnoses, including genetic disorders.
• Medical treatment determination: Determines medication effectiveness and dosage based on a person's genetic makeup (i.e. pharmacogenomics).

Genetic Disease

• Permanent changes in DNA, called mutations, often cause genetic diseases.
• Mutations can involve one gene (e.g., sickle cell anemia, cystic fibrosis) or multiple genes (e.g., Alzheimer's disease, diabetes).
• Environmental factors can trigger the onset of certain genetic diseases.
• Abnormalities in chromosome structure or number can lead to genetic diseases, such as Down syndrome.

Genetic Discrimination

• Increased ability to identify genetic differences raises concerns about the proper use of this information.
• Genetic discrimination can occur in the workplace and from health insurance issuers.
• The Genetic Information Nondiscrimination Act (GINA) of 2008, prohibits discrimination based on genetic information by employers and health insurance issuers.
• Other legal protections exist against genetic discrimination.
• The Americans with Disabilities Act (ADA) of 1990 protects against genetic discrimination in the workplace.

Genetic Engineering

• Genetic engineering involves the modification of an organism's genes.
• It can transfer desirable characteristics across species (e.g., strawberry plants resistant to cold, bacteria to devour oil spills).

Clone

• Cloning describes the process of creating a genetically identical replica of a cell, tissue, or organism.
• Gene cloning: Creates exact copies of DNA segments (genes).
• This is useful for gaining information about the gene sequence and making changes to the segment to place it into a different organism.
• Therapeutic cloning: Produces copies of embryonic stem cells for tissue/organ repair.
• Reproductive cloning: Produces exact copies of entire animals.

Clone Continued

• Reproductive cloning involves creating entire copies of animals.
• Dolly the sheep was a famous example.
• Cloning often has low success rates.
• Cloned animals may suffer from developmental problems.
• Scientists use cloning to model human diseases and possibly revive endangered species for animal conservation.

Exceptions to the Rule

• Cloning animals for medical purposes, like producing insulin or growth hormone.
• Producing animal organs or tissues for transplantation.
• Ethical concerns related to animal cloning and the use of animals in scientific research led to various objections.

Ethical Concerns

• Human cloning raises ethical questions surrounding the safety, well-being of cloned humans and broader societal implications.
• Risk of unforeseen health-related issues for cloned humans.
• Concerns over potential misuse, discrimination or exploitation among the cloned, ethical implications if cloning were to become easily accessible.
• Laws restricting or banning human cloning are present in some but not all countries.

Gene Therapy

• Treating diseases by inserting functioning genes into cells with abnormal/absent gene elements.
• Gene therapy is potentially a powerful tool for correcting genetic diseases.
• Special diets can correct compounds toxic to patients with certain genetic disorders.
• vitamins or other agents may be used to correct biochemical pathways.
• Other treatment approaches may be available (organ/tissue transplantation).

Gene Therapy Continued

• Somatic gene therapy: Corrects genetic defects in body cells, only affecting the individual patient.
• Germ-line gene therapy: Corrects disorders in reproductive cells, affecting future generations. This approach is a contentious area in current genetic research.

Infertility

• Infertility affects 10-15% of reproductive-age couples in the U.S.
• Options for couples experiencing infertility include in vitro fertilization (IVF), artificial insemination, surrogacy.

Surrogate/Adoption

• A surrogate mother carries a child for another couple.
• Types of surrogacy (gestational or traditional).
• Legal and ethical considerations surrounding surrogacy.
• Details about adoption policies, including national and state regulations.

Children's Rights

• Common law establishes parental rights to make healthcare decisions for minors.
• The doctrine of parens patriae allows the state to override parental decisions in a child's best interest.
• Severe disabilities and medical considerations can affect treatment decisions for infants and newborns, especially in terms of withholding life-sustaining care.

Abandonment

• Laws protecting children from abandonment.
• "Safe haven laws" exist to allow parents to safely abandon newborns without fear of legal repercussions, under certain jurisdictions.

This quiz explores key concepts in genetics, including pharmacogenetics, genetic diseases, and discrimination based on genetic information. It also covers significant legislation like GINA and HIPAA, as well as the Human Genome Project's impact on our understanding of genetics.