so i’m guessing that you’re looking at a population of many cells that have a DNA content that ranges from 2N (which is normal) to 4N (which can be .. normal or abnormal).

Anyways, i’m not sure if I completely understand your question… so, i’m not sure if i’ve given you a good hint. (do you have any more information?)

– kim

I’d guess these cells are in G1. They have just finished mitosis because some of them still have 4n DNA. Most of them are just living their lives (G1) and have 2n DNA.

Actually it looks like a completely normal population of cells to me.

Cells with 2n DNA content will be in G1 and cells with 4n will be in G2 or M phase. All the cells with between 2n and 4n will be in S phase.

But I’ve probably missed something if your question says they are not healthy cells.

The diagram on this site shows the amount of DNA present in each part of the cell cycle: 2n for G1, 4n for G2 and between 2n and 4n for S. I’m not sure about M phase and this site doesn’t really help with that but I don’t think you could really distinguish M and G2 phase with this type of diagram.

http://www.barrettsinfo.com/content/5_h … .htm#cycle

According to another site the difference between cancerous cells and normal ones in this type of diagram is the hight of the peak at 4n. In normal cells it should be below 6% (depending on cell type) but in cancerous cells it is higher. You also get more cells in S phase in a cancerous population.

I would just label the 4n peak with G2 and M phase.

the cell cycle is an all-or-nothing process a cell can undergo. There are several ‘checkpoints’ during the cell cycle and when the demands for the checkpoint in the G1-phase has been fullfilled, the cell completely undergoes the S-phase. That’s why so less cells have a DNA-content of 3n. Onbly cells that are replicating DNA at the instant you examine the DNA-content can have this amount of DNA.

More about checkpoints during the cell cycle can be found in Molecular Biology of the Cell, by Alberts et al.