XY sex-determination system
method of determining sex
The XY sex-determination system is a sex-determination system present in many mammals (including humans), some insects (Drosophila), some snakes, some fish (guppies), and some plants (Ginkgo tree).
In this system, the karyotypic sex of an individual is usually determined by a pair of sex chromosomes. Typically, karyotypic females have two of the same kind of sex chromosome (XX), and are called the homogametic sex. Karyotypic males typically have two different kinds of sex chromosomes (XY), and are called the heterogametic sex. In humans, the presence of the Y chromosome is responsible for triggering male phenotypic development; in the absence of the Y chromosome, the individual will usually develop phenotypicaly female. In most species with XY sex determination, an organism must have at least one X chromosome in order to survive.
The XY system contrasts in several ways with the ZW sex-determination system found in birds, some insects, many reptiles, and various other animals, in which the heterogametic sex is female. A temperature-dependent sex determination system is found in some reptiles and fish.
Mechanisms
All animals have a genome made of DNA, which forms chromosomes during cell division. In humans, most mammals, and some other species, two of the chromosomes, called the X chromosome and Y chromosome, contain genes which code for sex.
The public source identifies “XY sex-determination system” as method of determining sex. This brief keeps that definition visible, then builds a research path around sex-determination, system and method.
Why this record matters
A short description can identify a subject without explaining its stakes. For “XY sex-determination system”, the useful work is to connect “method of determining sex” to the records capable of establishing context and consequence.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Jun 8, 2026. The linked authority identifier is Q1604486. None of the 0 selected statements returned an explicit reference.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “XY sex-determination system”, its source revision and the description used here.
- Expand the search: follow XY sex-determination system primary sources, XY sex-determination system archive and sex-determination research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “XY sex-determination system”?
- What terminology or title could unlock a more precise catalogue search?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “XY sex-determination system” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.