# Chromosome

> A chromosome is one long DNA molecule packaged with proteins that carries many genes; cannabis normally has 10 pairs, nine autosome pairs plus an X/Y sex pair.

- Canonical: https://genetixbay.com/knowledge/glossary/chromosome.html
- Also written: chromosomes, chromosome pair, autosome, autosomes, karyotype
- Glossary category: Genetics and breeding · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

A chromosome is a single long DNA molecule, wrapped around proteins, carrying hundreds to thousands of [genes](https://genetixbay.com/knowledge/glossary/gene.md) in a fixed order. Cannabis is [diploid](https://genetixbay.com/knowledge/glossary/diploid.md) with 2n = 20: nine pairs of autosomes plus one pair of [sex chromosomes](https://genetixbay.com/knowledge/glossary/xy-sex-determination.md), XX in females and XY in males (Divashuk et al. 2014).

## In practice

Chromosomes are why genes travel in groups. During meiosis each pair separates, so every pollen grain and ovule receives one copy of each of the ten chromosomes, with some segments swapped between the pair by crossing over. Genes on different chromosomes assort independently; genes close together on one chromosome are linked.

Growers meet chromosomes most directly through sex. A female (XX) reversed to make pollen still only carries X chromosomes, so its pollen gives all-female (XX) seed. That is the basis of [feminised seed](https://genetixbay.com/knowledge/glossary/feminised-seed.md).

Some cultivated plants have extra whole sets of chromosomes ([polyploids](https://genetixbay.com/knowledge/glossary/polyploid.md)). Triploid and tetraploid cannabis exist, mostly from deliberate breeding.

## Don't confuse with

- **Genome**: the full DNA content of a cell across all chromosomes.
- **Gene**: a small part of one chromosome.
- **Chromatid**: one of the two copies of a chromosome after it has duplicated before cell division.

## Related terms

[Gene](https://genetixbay.com/knowledge/glossary/gene.md), [Locus](https://genetixbay.com/knowledge/glossary/locus.md), [Diploid](https://genetixbay.com/knowledge/glossary/diploid.md), [XY sex determination](https://genetixbay.com/knowledge/glossary/xy-sex-determination.md), [Linkage](https://genetixbay.com/knowledge/glossary/linkage.md)

## Read more

- [Mendelian genetics for growers, with Punnett squares](https://genetixbay.com/knowledge/breeding/mendelian-genetics-for-growers.md)

## Sources

1. Divashuk MG, Alexandrov OS, Razumova OV, Kirov IV, Karlov GI. 2014. Molecular cytogenetic characterization of the dioecious Cannabis sativa with an XY chromosome sex determination system. PLoS ONE 9(1):e85118. https://doi.org/10.1371/journal.pone.0085118
2. Prentout D, Razumova O, Rhone B, et al. 2020. An efficient RNA-seq-based segregation analysis identifies the sex chromosomes of Cannabis sativa. Genome Research 30(2):164-172. https://doi.org/10.1101/gr.251207.119