How to picture segment data on a Chromosome

Question

I'm lost in the weeds. Hoping an expert can answer and point me to a good source for additional background.

I've been using DNA painter to "paint" my chromosomes. I'm interested in representing this data in a picture and color a chromosome based on ancestors. Rather than using a straight line for the chromosome, I wanted to use a more representative shape of an actual chromosome, roughly an X shape for chromosome one. I'm confused on how to map the segment data onto the X shape. I see the centromere position in DNA painter - so that helps identify the center of the X. However, a rough X shape would have four arms emanating from the center (centromere) - whereas the straight line only has two arm. So if a have a 10 cM segment, starting in position 1 on the paternal chromosome 1 and assign it the color red, would I color the beginning portion of both bottom legs of the roughly shaped X red? Or have I misunderstood something basic? Perhaps the centromeres are where the paternal and maternal chromosomes copies intersect?

Answer 1

That X shape is only seen for a brief time when the cell is in the process of dividing and needs to make copies of each chromosome. DNAPainter is set up to show the paternal and maternal chromosomes separately, which is how they spend most of their time.

Answer 2

Basically, you can depict it any way you wish, but it will certainly not be realistic. DNApainter has a more readily comprehensible & extremely simplified representation of a “number line mapping” of segments along the chromosomes (but not the Y or mitochondrial DNA). I would recommend the dnapainter type representation for its approachability and ease of use. If you still want additional complexity, before you pursue it too much, take a look at the UCSC website for a mapping of the human genome & you may glimpse a hint of the immensity of what is not displayed by any of the genealogical DNA testing site data.