U. S. National Library of Medicine

Cells and DNA - Cells, genes, and chromosomesMutations and Health - Gene mutations, chromosomal changes, and conditions that run in familiesHow Genes Work - Proteins, cell growth, and cell divisionGene Families - Groups of genes that share important characteristicsInheriting Genetic Conditions - Inheritance patterns and understanding riskGenetics and Human Traits - How genes influence various human characteristicsGenetic Consultation - Finding and visiting a genetic counselor or other genetics professionalGenetic Testing - Benefits, costs, risks, and limitations of genetic testingNewborn Screening - Testing all babies in their first days of life for certain disorders and conditionsGene Therapy - Experimental techniques, safety, ethics, and availabilityThe Human Genome Project - Sequencing and understanding the human genomeGenomic Research - Next steps in studying the human genomePrecision Medicine - Disease treatment and prevention strategies tailored to variability in genes, environment, and lifestyle

A gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. Mutations range in size; they can affect anywhere from a single DNA building block (base pair) to a large segment of a chromosome that includes multiple genes. Gene mutations can be classified in two major ways: - Hereditary mutations are inherited from a parent and are present throughout a person's life in virtually every cell in the body. These mutations are also called germline mutations because they are present in the parent's egg or sperm cells, which are also called germ cells. When an egg and a sperm cell unite, the resulting fertilized egg cell receives DNA from both parents. If this DNA has a mutation, the child that grows from the fertilized egg will have the mutation in each of his or her cells.- Acquired (or somatic) mutations occur at some time during a person's life and are present only in certain cells, not in every cell in the body. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if a mistake is made as DNA copies itself during cell division. Acquired mutations in somatic cells (cells other than sperm and egg cells) cannot be passed on to the next generation.

A particular disorder might be described as "running in a family" if more than one person in the family has the condition. Some disorders that affect multiple family members are caused by gene mutations, which can be inherited (passed down from parent to child). Other conditions that appear to run in families are not caused by mutations in single genes. Instead, environmental factors such as dietary habits or a combination of genetic and environmental factors are responsible for these disorders. It is not always easy to determine whether a condition in a family is inherited. A genetics professional can use a person's family history (a record of health information about a person's immediate and extended family) to help determine whether a disorder has a genetic component. He or she will ask about the health of people from several generations of the family, usually first-, second-, and third degree relatives.

This book will cover the following questions: What are proteins and what do they do? How do genes direct the production of proteins? Can genes be turned on and off in cells? What is the epigenome? How do cells divide? How do genes control the growth and division of cells? How do geneticists indicate the location of a gene?

This book will answer these Questions: Are fingerprints determined by genetics? Is eye color determined by genetics? Is intelligence determined by genetics? Is handedness determined by genetics? Is the probability of having twins determined by genetics? Is hair texture determined by genetics

Table of Contents: Cells and DNAHow Genes WorkMutations and HealthInheriting Genetic ConditionsGenetic ConsultationGenetic TestingGene TherapyThe Human Genome ProjectGenomic Researc