Genetics Index Glossary

The Extremes in Chromosome Number


What are the minimum and maximum number of chromosomes?

  • The record for minimum number of chromosomes belongs to a subspecies of the ant Myrmecia pilosula, in which females have a single pair of chromosomes. This species reproduces by a process called haplodiploidy, in which fertilized eggs (diploid) become females, while unfertilized eggs (haploid) develop into males. Hence, the males of this group of ants have, in each of their cells, a single chromosome.

  • The record for maximum number of chromosomes is found in found in the fern family. Polyploidy is a common conduction in plants, but seemingly taken to its limits in the Ophioglossum reticulatum. This fern has roughly 630 pairs of chromosomes or 1260 chromosomes per cell. The fact that these cells can accurately segregate these enormous numbers of chromosomes during mitosis is truly remarkable.

References and Reviews
  • Gould SJ: The Ant and the Plant. In: Bully for Brontosaurus, W.W. Norton & Co., New York, 1991.

Last updated on January 30, 1998
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