Hello,
I was wondering how many cell types are differentiated in C elegans. I read that there are 118 different types of neural cells but didn´t find the total number or even an estimate about the different cell types of the other somatic cells in an adult hermaphrodite.
Best regards, Christian
It is not simple to come up with one solid answer for your question. Since some bilateral “pairs” of neurons seem to accomplish different functions, even that listing of “118” different neuron types is subject to question. ASEL is not the same as ASER, etc. But some workers would prefer to squeeze many similar cells into just a few baskets. So one might even list the possible cell types as neuron, muscle, somatic gonad, pharynx, intestine, germline, etc. There are just over 1000 somatic cells in the hermaphrodite, and by this lumping one might squeeze them into perhaps one dozen baskets?
So to some extent it is a matter of taste. On WormAtlas we have tried to subdivide all cells into tissue types first, and then with further descriptions, we have subdivided those tissues into multiple cell types. We started with seven major tissues. Some tissues involve just one cell type (coelomocyte), some involve dozens of cell types. The nervous system may involve 118, more or less, depending on how much lumping one agrees to.
The male animal has more somatic cells and more cell types, perhaps 40-50% higher than the hermaphrodite!
Furthermore, some cell types are temporary, and do not last until adulthood, including cells that die immediately upon their birth, cells that adopt an early fate, and switch later to a second fate, or cells that carry out an embryonic role, but later die in the larval animal. Depending on how one accounts for these intermediate cell fates, your total number of cell types is still drifting higher.
I could go on further, but that will require dozens of pages of explanation. Still working on that. My apologies for not answering sooner.
David Hall