MEDLINEplus Health Information: Return to home page   A service of the National Library of Medicine: Go to NLM home page
Search     Advanced Search    Site Map    About MEDLINEplus    Home
Health Topics: conditions, diseases and wellness Drug Information: generic and brand name drugs Dictionaries: spellings and definitions of medical terms Directories: doctors, dentists and hospitals Other Resources: organizations, libraries, publications, MEDLINE

Medical Encyclopedia

Disease     Injury     Nutrition     Poison     Special     Surgery     Symptoms     Tests


Chromosomes and DNA
 
Overview   

Chromosome



Alternative names:
chromosomes

Information:
Humans have 46 chromosomes. There are a total of 23 pairs of chromosomes or 46 total chromosomes. All of the body's genes are contained within these 46 chromosomes.

Two of the chromosomes, the X and the Y chromosome, determine sex and are called the SEX CHROMOSOMES. Females have 2 X chromosomes and males have 1 X and 1 Y chromosome. The Y chromosome determines the male sex but does little else.

The remaining 44 chromosomes are called AUTOSOMAL CHROMOSOMES. Chromosomes exist in pairs. For convenience, scientists have numbered the autosomal chromosome pairs 1 through 22. The X and Y chromosome are the 23rd pair.

Each parent contributes one half of each pair or 23 chromosomes to their child, 22 autosomal and 1 sex chromosome. Females always contribute an X chromosome to the child while a male may contribute an X or a Y. Therefore, it is the male that determines the sex of the child.

RELATED TOPICS:
autosomal dominant
autosomal recessive
genetic counseling and prenatal diagnosis
sex-linked dominant
sex-linked recessive

For detailed information, see heredity and disease (genetics).



Adam

The information provided herein should not be used for diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Copyright 2000 adam.com, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Health Topics | Drug Information | Dictionaries | Directories | Other Resources