# De Novo on Y chromosome?

**URL:** <https://discuss.hail.is/t/de-novo-on-y-chromosome/2629>\
**Category:** Hail Query & hailctl\
**Created:** [April 23, 2022, 3:19am UTC](https://discuss.hail.is/t/de-novo-on-y-chromosome/2629 "2022-04-23T03:19:09Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![genome](https://avatars.discourse-cdn.com/v4/letter/g/9f8e36/32.png) [@genome](https://discuss.hail.is/u/genome)\
**Post date:** [April 23, 2022, 3:19am UTC](https://discuss.hail.is/t/de-novo-on-y-chromosome/2629/1 "2022-04-23T03:19:09Z")

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Hi all, I am wondering if `hl.de_novo` also calls _de novo_ mutations on the Y chromosome? Thank you very much.

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**Author:** ![kyle](https://yyz2.discourse-cdn.com/flex036/user_avatar/discuss.hail.is/kyle/32/11_2.png) [@kyle](https://discuss.hail.is/u/kyle)\
**Post date:** [April 27, 2022, 1:12pm UTC](https://discuss.hail.is/t/de-novo-on-y-chromosome/2629/2 "2022-04-27T13:12:20Z")

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You can read this thread – [De novo calls on hemizygous X variants](https://discuss.hail.is/t/de-novo-calls-on-hemizygous-x-variants/2357) – for my slow realization that the answer to that question is “no” (since the caller looks for situations where the child’s genotype is het, and the VCF won’t report variants that way in hemizygous regions) and for the way I modified the caller to help it work.

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**Author:** ![tpoterba](https://yyz2.discourse-cdn.com/flex036/user_avatar/discuss.hail.is/tpoterba/32/61_2.png) [@tpoterba](https://discuss.hail.is/u/tpoterba)\
**Post date:** [April 27, 2022, 1:36pm UTC](https://discuss.hail.is/t/de-novo-on-y-chromosome/2629/3 "2022-04-27T13:36:44Z")

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Thanks, Kyle! Was about to point this thread in that direction.