# X0 sex-determination system

> sex-determination system, with only 1 sex chromosome (“X”); males only have 1 X chromosome (X0); females have 2 (XX); found in most arachnids, many insects, some nematodes, some crustaceans, some molluscs, and some fish (e.g. Ancistrus)

**Wikidata**: [Q607251](https://www.wikidata.org/wiki/Q607251)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/XO_sex-determination_system)  
**Source**: https://4ort.xyz/entity/x0-sex-determination-system


## References

1. Freebase Data Dumps. 2013