# Low diversity in mapped results

**URL:** <https://community.brain-map.org/t/low-diversity-in-mapped-results/4398>\
**Category:** MapMyCells\
**Tags:** analysis\
**Created:** [May 11, 2025, 7:38pm UTC](https://community.brain-map.org/t/low-diversity-in-mapped-results/4398 "2025-05-11T19:38:03Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![danielsf](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/danielsf/32/209_2.png) [@danielsf](https://community.brain-map.org/u/danielsf)\
**Post date:** [May 12, 2025, 2:57am UTC](https://community.brain-map.org/t/low-diversity-in-mapped-results/4398/2 "2025-05-12T02:57:28Z")

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As a first pass, [this post](https://community.brain-map.org/t/cell-typing-different-based-on-clustering/4319/4) lists some things you might look at to assess what is happening. The fact that all of your cells are mapping to the alphabetically first class in the taxonomy is a little suspicious to me. Maybe your dataset doesn’t have any of the marker genes we are looking at. Or maybe the expression in the marker genes is so low that that the correlation coefficients between cells and cell types is effectively random.

If you feel comfortable, I could take a peek at your data and see if there is anything peculiar about it. I would just be looking at

a) what genes are present  
b) what the distribution of numerical values in the cell-by-gene matrix is

If you shared with me the name of your output file package (the .zip file you downloaded from MapMyCells), I might be able to track it down in the MapMyCells pipeline.

Again: only if you’re comfortable with that

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