What Are the Chromosomes in Your DNA?
Chromosomes determine traits like eye color, hair color, and height.
Encyclopædia Britannica, Inc.
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© MinuteEarth (A Britannica Publishing Partner)The aging process in an organism may depend in large part on its ability to repair the chromosomes in its cells. Learn about differences in the aging process between human beings, naked mole rats, and the jellyfish Turritopsis dohrnii.
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Encyclopædia Britannica, Inc.The terms haploid and diploid refer to the number of chromosomes in each cell.
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Encyclopædia Britannica, Inc.A video about sex chromosomes and the inheritance of biological sex.
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Encyclopædia Britannica, Inc.The process of cell division begins with cell growth and nuclear doubling and ends with cytokinesis, the physical separation of the two identical daughter cells.
News •
Weakened chromosome anchors may help explain age-related declines in egg quality
• Oct. 26, 2026, 1:40 PM ET (Medical Xpress)
Transcript
Inside your cells, and inside the cells of every living thing, there is DNA.
DNA makes up your genes, which contain the hereditary information that gets passed from generation to generation.
The information that genes carry helps determine an organism’s traits, such as flower color in plants or height in humans.
DNA strands take the form of a double helix.
In eukaryotic organisms, like animals and plants, long strands of DNA are wound around small proteins called histones.
DNA wound around histones creates structures called nucleosomes.
Nucleosomes are linked together, coiled, and condensed further into threadlike strands called chromatin.
DNA spends most of its time in these chromatin strands, floating around the nucleus of a cell.
But before a cell divides, the chromatin is coiled even more tightly into structures called chromosomes.
Each species has a particular number of chromosomes.
In eukaryotic organisms, the chromosomes are carried in pairs within each cell of the body. One chromosome in each pair is inherited from the father and one from the mother. Humans have 23 chromosome pairs.
The chromosomes within a pair have genes coding for the same trait, such as the gene that codes for eye color. But the two chromosomes could hold different versions of the same gene. For example, the gene on one chromosome may code for blue eyes while the gene on the other codes for brown. These alternate versions of the same gene are called alleles.
DNA makes up your genes, which contain the hereditary information that gets passed from generation to generation.
The information that genes carry helps determine an organism’s traits, such as flower color in plants or height in humans.
DNA strands take the form of a double helix.
In eukaryotic organisms, like animals and plants, long strands of DNA are wound around small proteins called histones.
DNA wound around histones creates structures called nucleosomes.
Nucleosomes are linked together, coiled, and condensed further into threadlike strands called chromatin.
DNA spends most of its time in these chromatin strands, floating around the nucleus of a cell.
But before a cell divides, the chromatin is coiled even more tightly into structures called chromosomes.
Each species has a particular number of chromosomes.
In eukaryotic organisms, the chromosomes are carried in pairs within each cell of the body. One chromosome in each pair is inherited from the father and one from the mother. Humans have 23 chromosome pairs.
The chromosomes within a pair have genes coding for the same trait, such as the gene that codes for eye color. But the two chromosomes could hold different versions of the same gene. For example, the gene on one chromosome may code for blue eyes while the gene on the other codes for brown. These alternate versions of the same gene are called alleles.
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