Chromosome set

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Chromosome inventory of a lymphocyte from a female human: 46 chromosomes .
The micrograph shows colored metaphase chromosomes, each with two chromatids .
Karyogram of a female human - pairwise assignment of the double set of chromosomes

In the genetics of eukaryotes, the chromosome set describes the number of chromosomes in the nucleus of a cell .

If the chromosomes of a eukaryotic cell are examined more closely and compared with one another, chromosomes of the same size are often found that also contain homologous genes . If the cell nucleus has two such homologous chromosomes that correspond to one another , the cell has a double set of chromosomes (2 n ); this is known as diploid . In humans, like most vertebrates , this condition is present in most of the body cells , they have a double set of chromosomes. In humans this is a total of 46 chromosomes: two copies each of chromosome 1 , from chromosome 2 and so on to chromosome 22 (44 autosomes ) and two sex chromosomes (2 gonosomes ), namely two X chromosomes in females or one X and one Y -Chromosome in males.

Human germ cells, on the other hand, have a simple set of chromosomes (1 n ), they are haploid , since the number of chromosomes per cell was halved by the reduction division in meiosis . A simple human chromosome set consists of 23 chromosomes ( n = 23), namely one chromosome 1, one chromosome 2 and so on up to chromosome 22 and one sex chromosome, i.e. the X chromosome or the Y chromosome.

If a cell has a normal set ( s ) of chromosomes or an integer multiple thereof (2 n , 3 n , ...), it is euploid . If there is a different number of chromosomes, i.e. too many or too few chromosomes, this is called aneuploidy .

Names depending on the number of chromosome sets

  1. Haploidy , simple set of chromosomes
  2. Diploidy , double set of chromosomes
  3. Triploidy , triple set of chromosomes
  4. Tetraploidy , quadruple set of chromosomes

A multiple set of chromosomes over 2 n is also called polyploidy .

The number of chromosome sets can be used to classify organisms:

The composition of chromosome sets can be used to characterize cell states:

See also


  • Werner Buselmaier, Gholamali Tariverdian: Human Genetics . 4th edition. Springer Medizin Verlag, Heidelberg 2006, ISBN 978-3-540-32677-9 , p. 123 .