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Chromosome Mapping New Features

Finally! A cM slider for chromosome maps

cM slider poster

What is it? A new feature for chromosome maps at DNA Painter: a centimorgan slider, allowing you to hide segments below a certain size

Why would I use it? This will be useful if you have a map with segments of different sizes and want to ignore smaller ones temporarily

What do I need in order to do this? The feature is now available in all chromosome maps. Just go to the settings area and click the relevant option to turn it on.

Several years after it was first requested, I have recently released a ‘cM slider’: a way to show and hide segments based on centimorgans. This is now an option that can be turned on in any chromosome map at DNA Painter. It’s simple but quite powerful!

The new option

When you click the settings cog above chromosome 1, you’ll now see a new option: Show slider to restrict segment display?

The settings cog above chromosome 1
The settings cog above chromosome 1
The option to turn on the cM slider
The option to turn on the cM slider

Once you click this, you’ll see default lower (5cM) and upper (30cM) bounds for the slider. You can adjust these at any time by changing the numbers.

The cM slider options for lower and upper bounds
The cM slider options for lower and upper bounds

The slider

The cM slider showing above chromosome 1 once active
The cM slider showing above chromosome 1 once active

As long as you have this option checked, the slider will appear.

  • When you first turn it on, the slider will hide segments below 7cM by default
  • You can drag the slider handle to the left or right to adjust the view, hiding only segments that are smaller than the selected value
  • Please note: if your segment does not have a cM value defined, then it will display all the time, regardless of your slider settings

The cM slider in action

Here are some views of one of my maps with the slider

My map with the slider activated with the default setting, hiding segments under 7cM
My map with the cM slider activated with the default setting, hiding segments under 7cM
My map with the slider moved so that segments under 30cM are hidden
My map with the slider moved so that segments under 30cM are hidden

Saved configuration for the cM slider

As with other DNA Painter map settings, the site saves your choices on a ‘browser and map’ basis. This means if you turn the slider on while using the Chrome Browser on your home computer and adjust the lower bound to 3cM and the upper to 40cM, then this browser on this computer will retain these settings. I’m still working towards centralised settings that you’ll be able to apply to any map.

Acknowledgements

Thanks to everyone in the DNA Painter User Group who has (repeatedly) requested this, and in particular to Andrew from Australia who went beyond the call of duty by actually emailing me some code to set me on my way.

Contact info: @dnapainter.bsky.social / jonny@dnapainter.com