[Zaak]

> is meiosis and mitosis the only two way to reproduce?

Well, from a high-level view the only way a cell can make more cells is to divide, and if it divides it either makes a copy of its genetic material first, or gives half of it to each daughter cell. So in that sense, they're the only two ways possible.

From a more detailed view, I wonder if the machinery of meiosis is evolutionarily the same in every sexually-reproducing species, or if it has evolved more than once. My guess is only once, because it has a specific sequence of events which is always the same.

[hammock]

>Well, from a high-level view the only way a cell can make more cells is to divide, and if it divides it either makes a copy of its genetic material first, or gives half of it to each daughter cell. So in that sense, they're the only two ways possible.

Ignoring the idea of three-way (or more) genetic swaps, which would be like another type of meiosis, what if there were other ways?

What if there was a "carbon copy" or "embossing" technique where a cell bumps it's genes up against other's genes, and through some process yet to be determined , the other's genes are "nudged" into conforming to the shape of the cell's bumping it?

Sort of like picking a lock.. you bump up against each cylinder enough times until it falls into the shape you want it to. No splitting of chromosomes, or transfer of actual genetic material needed.

Of course this is a pipe dream but I'm just imagining here.

[vikramkr]

Interesting thought. Theres no way for that to work with DNA really, since information is included there in a chemical sequence rather than a shape necessarily. Though there are epigenetic aspects that could maybe work that way, but that's not in the spirit of what you proposed. Maybe an alien form of life with a different information storage mechanism.

Right here at home though, if you want a life-approximating thing that actually does reproduce that way, you're in luck. Prions are proteins (a type of biological molecule) that make more of themselves in pretty much that way. They arent alive and they arent cells, but they reproduce by bumping into normally shaped proteins and making them be shaped in the same way. They cause all sorts of terrible diseases like mad cow and tend to be incurable since, well, theres really not much to kill or stop, it's just a protein, making other proteins look the same way, very fascinating and very scary - there are hypothesis that suggest prion like processes could be involved in neurodegenerative diseases like alzheimers.

https://en.wikipedia.org/wiki/Prion

[205guy]

Isn't that what we call a "virus"?

[greglindahl]

You might want to read upon horizontal gene transfer. But it's not reproduction.

[hammock]

Yes- this + mitosis of the new genetic code at sufficient scale would approximate a new form of reproduction.. there could be some organism that relies on it