What are genes?

A gene is the basic physical and functional unit of heredity. The human body (and animal or plant bodies often too) is made up of trillions of tiny cells. Most have a sort of headquarters, the nucleus that contains your genes.  Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. However, many genes do not code for proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases.

What is genetics?

Genetics is the science of these genes. It is the science of inheritance, how traits such as hair color, eye color, and risk for disease are passed (“inherited”) from parents to their children.

Genetics studies how different genetic qualities, called traits, are passed down from parent to child. Genetics helps explain what makes you unique, why family members look alike, and why some diseases run in families. When we trace the paths of these qualities, we are following packages of information called genes. Your mix of genes is unique to you—even your full brothers or sisters have a slightly different mix. Genes are instructions for building the parts of your body and doing the work that keeps you alive, from carrying oxygen to digesting to food and everything else we do. The genes are grouped into collections called chromosomes. Most humans have 23 pairs of chromosomes.

• Jewish Genetic Conditions
• Compassionate Allowances Conditions (CAL)
• Cystic Fibrosis
• Down syndrome (trisomy 21)
• Down syndrome risk calculator
• Patau syndrome (trisomy 13)
• Edward syndrome (trisomy 18)
• Cri du chat syndrome (5p- syndrome)

Table of Contents: Help Me Understand Genetics

1. Cells and DNA  - Cells, genes, and chromosomes
2. How Genes Work - Proteins, cell growth, and cell division
3. Mutations and Health - Gene mutations, chromosomal changes, and conditions that run in families
4. Inheriting Genetic Conditions - Inheritance patterns and understanding risk
5. Genetic Consultation - Finding and visiting a genetic counselor or other genetics professional
6. Genetic Testing - Benefits, costs, risks, and limitations of genetic testing
7. Gene Therapy - Experimental techniques, safety, ethics, and availability
8. The Human Genome Project - Sequencing and understanding the human genome
9. Genomic Research - Next steps in studying the human genome

The "Help Me Understand Genetics" section is from the National Library of Medicine NLM and presents basic information about genetics in clear language and provides links to online resources. 

From: National Library of Medicine (NLM)