Skip to content

    Genetics

    Font Size
    A
    A
    A

    Topic Overview

    What are genes?

    Genes are the part of a body cell that contain the biological information that parents pass to their children. Genes control the growth and development of cells. Genes are contained in DNA (deoxyribonucleic acid), a substance inside the center (nucleus) of cells that contains instructions for the development of the cell.

    You inherit half of your genetic information from your mother and the other half from your father. Genes, alone or in combination, determine what features (genetic traits) a person inherits from his or her parents, such as blood type, hair color, eye color, and other characteristics, including risks of developing certain diseases. Certain changes in genes or chromosomes may cause problems in various body processes or functions.

    What are chromosomes?

    Many genes together make up larger structures within the cell called chromosomes. Each cell normally contains 23 pairs of chromosomes.

    A human has 46 chromosomes (23 pairs). One chromosome from each pair comes from the mother, and one chromosome from each pair comes from the father. One of the 23 pairs determines your sex. These sex chromosomes are called X and Y.

    • For a child to be female, she must inherit an X chromosome from each parent (XX).
    • For a child to be male, he must inherit an X chromosome from his mother and a Y chromosome from his father (XY).

    Some genetic disorders are caused when all or part of a chromosome is missing or when an extra chromosome or chromosome fragment is present.

    What is genetic testing?

    Genetic testing examines a DNA sample for gene changes, or it may analyze the number, arrangement, and characteristics of the chromosomes. Testing may be performed on samples of blood, semen, urine, saliva, stool, body tissues, bone, or hair.

    1 | 2 | 3
    1 | 2 | 3

    WebMD Medical Reference from Healthwise

    Last Updated: March 12, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
    Next Article:

    Hot Topics

    WebMD Video: Now Playing

    Click here to wach video: Dirty Truth About Hand Washing

    Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

    Click here to watch video: Dirty Truth About Hand Washing

    Popular Slideshows & Tools on WebMD

    disciplining a boy
    Types, symptoms, causes.
    fruit drinks
    Eat these to think better.
    embarrassed woman
    Do you feel guilty after eating?
    diabetes supply kit
    Pack and prepare.
    handful of vegetables and vitamins
    Diet tips and mistakes.
    birth control pills
    Which kind is right for you?
    Remember your finger
    Are you getting more forgetful?
    sticky notes on face
    10 tips to clear your brain fog.
    Close up of eye
    12 reasons you're distracted.
    Trainer demonstrating exercise for RA
    Exercises for your joints.
    apple slices with peanut butter
    What goes best with workouts?
    woman having a good day
    Revitalize your life.

    Women's Health Newsletter

    Find out what women really need.