I don't quite understand the whole geneseed thing.

How do the chapters increase their numbers? Can the only rebuild?

Does the destruction of a geeneseed mean that the chapter is permantely down one man?

Do the grow new geneseeds or is there a finate supply?

Can you take the geneseed out of a living marine and put it in an aspirant, resulting in a new marine while keeping the old one?

Unless they have changed things, there are several ways to increase the supply of geneseed.

The first method is using vat grown clones to produce more geneseed. This is the method used to produce the initial run of geneseed when building a chapter.

The second is that every full space marine has two geneseeds upon reaching their full status. One I believe is in the chest, the other at the base of the spine. While implanting the black carapace, the geneseed at the base of the spine is removed. The one in the chest, remains to be removed on death.

The third is that each chapter gives some of their geneseed to the ad mech for testing and safe keeping. If a chapter is low on members and geneseed, and the chapter is deemed saveable, then geneseed can be sent to them from their parent chapter or from the supply sent by their own chapter.

I too was wondering this, I had a theory on 1 geneseed being implanted but 2 extracted. But then chaos seems to instead steal them from other chapters instead of using thier own most of the time.

Well that helps me understand some of the things related to forming new chapters. I was trying to figure out how chapters were created as I was thinking of doing such a thing if my Space Wolf dies in battle. But I have no idea on the process of making new chapter and such what all is actually detailed in it I've only read maybe Space Wolf book and the Lone Wolf graphic novel so far. But I thought it'd be good to form a new chapter just for the fun and no idea how the process works or how to make it sound good that it belongs with Prime Chapters or successor chapters.

I believe that every chapter is bound to tithe a percentage of their geneseed whenever it is harvested to the Adeptus Mechanicus for the dual purposes of testing to ensure purity from mutation as well as potential founding of new chapters. Once in a blue moon (which is hundreds, if not thousands of years for the IoM) the High Lords of Terra will decree that a new Chapter be created from the geneseed stored by the Mechanicus.

Are the geneseeds the same thing (meaning is the one in the chest different than the one on the spine)?

Both progenoid glands are identical. They collect genetic information from the Space Marine once he has completely incorporated his chapter's implants. This is the genetic information needed to make new marine implants. The progenoids require many years to collect the genetic material, partly because the marine must be completely aclimated to his implants. The neck gland matures after 5 years, the chest gland takes 10 years to mature. Either can be removed surgically at any point after maturation. Essentially his DNA merges with the DNA of the implanted geneseed, then the progenoid collects the DNA needed to make new implants from his body.

If a space marine dies before his progenoids are fully matures then the chapter looses 1 or 2 progenoids which could have been used for future marines. Barring early deaths, mutation, destruction (marine vaporized etc.), or lost/stolen every 1 marine can provide the geneseed needed to make 2 new marines. Because of deaths, mutation, destruction, and losses most chapters do not get the best possible turnaround. Thats why collecting any remaining progenoids from dying/dead marines is such an important thing.

Additionally, I believe that once the first progenoids are harvested, they are replaced with fresh ones. That way each marine creates potentially dozens of glands in their lifetime. This is borne out by hardened characters in novels [ie Hell's Reach] still having progenoids that required harvesting.

The glands can be removed as one novel had some marines going on a Suicide Mission and they had their glands removed before they left. Normally they leave them in as the surgery to remove them is complicated. However, the fluff over the 25 years has been a bit inconsistent as when the glands are removed except in the case of death. In other words 200 year old marines still with their glands, marines having them removed as soon as they mature, and all sorts of different things. They only thing I personally don't recall seeing are new glands being implanted after glands have been removed.

I've always been of the opinion marines left progenoids in the chest in to possibly improve the geneseed.

Once the neck is matured enough to facilitate genseed growth it is removed, so your basic marine can still 'sire' his successor without even if he were to die later. The one in the chest is allowed to remain. Over time the progenoid might continue to absorb DNA (well I'd assume it would anyways). This further genetic absorbtion can serve to further stabilize the geneseed in the progenoid. Or even be used to weed out undesirable characteristics.

Say Marine Bob is a goof up, or grows some mutations a few decades down the line. His geneseed would not want to be used to create new space marines but the apothecaries could examine his progenoid once he's killed and possibly determine any mutation in it. Thereby furthering their knowledge of possible mutations or diseases their chapters geneseed could develop and maybe create a method to counteract future contamination.

On the other hand Marine Fred proves to be an exceptional marine. Brave, valliant, strong, and capable. His Progenoids could absorb some of his DNA with the Primarch's DNA. A marine is after all an amalgamation of two genetic structures, his and his chapter's geneseed, its concievable the geneseed must absorbs some of the marines human DNA for it to grow. Apothecaries will have the knowledge of his positive atributes and would be able to track his geneseed recipients through many generations. Much like you would if you were breeding animals. Possibly allowing the Apothecaries to improve the quality of their chapters geneseed over time.

Not sure about the accuracy of this.

wh40k.lexicanum.com/wiki/Progenoid

No mention of replanting once the first 'crop' is mature, which would mean that Apothecaries only get to harvest from rookie marines, as everyone else's was taken out years ago...

So we have two models: the "regular harvesting of progenoids as soon as they mature" model, or the "only remove the progenoids upon the marine's death" model.

I personally favour the "regular harvesting of progenoids" concept, as it just makes sense to do that under surgical conditions on a regular basis. If you think about it, the alternative is that the chapter is totally reliant upon the dead marine's body being in a fit state to give up the progenoids. Given the number of truly lethal weapons in 40k (meltas, plasma guns etc) that are capable of totally disintegrating a body, this seems a hell of gamble.

Plus, if progenoids can only be harvested upon death, this means you could only recover progenoids every few decades. If more than 50% of progenoids are destroyed in battle, this approach would doom the chapter to a slow death. And that doesn't even include the tithed geneseed taken from the chapter by Imperial authorities.

As for the "leaving the progenoids in improves the geneseed" idea...well, I don't really like this concept. Inasmuch as the more long lived marines wil produce more geneseed over their lifetimes, (if the progenoids are regularly removed) there is a natural process of evolution (of a kind) going on here anyway, with the survival of the geneseed from longer lived (and by extension presumably more skilled) marines passing on to more marines each generation.

As for the reinstallation of progenoids after they're removed...perhaps they just grow back again naturally? As part of the marines extraordinary physiology?

Siranui said:

If they can both be taken out while the SM is alive why would you ever need to do it in combat? If they didn't grow back the guy would still probably be a scout after 10 years and you'd just rotate them back for surgical removal. And of course they'd probably be huge song and dance made about Marines that go 5 and 10 years.

On the other hand if they do grow back (which I'd never heard of) then you'd only need to have them report in every 5 years for extraction, a hundred year old SM would have produced enough GS for 30 SM's, hardly worth risking an experienced SM's life to pick up a GS on that scale. Unless you waste a lot of GS on failed SM's, but individual GS is still not that valuable.

Perhaps you can extract one but have to leave the other in. That way you are almost guaranteed to break even (baring the dumb scouts that die in the first 5 years but you need to get the ones back from dead marines to cover failures, losses and tithes.

Face Eater said:

In my mind, they are both extracted surgically after 20 years (or whenever), and another immature pair are inserted. Thus, most marines create quite a bit of seed during their lifetime. But that's not to say Chapters have tons kicking around spare. There's the tithe (which I assume is used for testing and starting new Chapters), and other testing, plus the 25%+ failure rate, some seed might not be up-to-par and would be discarded, and it's entirely imaginable that Chapters loose entire Companies in one foul swoop.

I don't see it as crucial to the survival of the Chapter that every last piece of seed is returned to the Chapter, but Chapters that have had a run of bad luck and taken heavy losses for a century or two, or Chapters with unstable seed might treasure every last gland. Plus there's the spiritual aspect: Geneseed is a legacy; the closest Marines can come to having children. Even if the Chapter has enough seed for survival, you can bet that every Marine **** well wants his seed recovered!

But that brings to question chapters that are on the verge of destruction. The Flesher Tearers for instance. They are in said to be in a pretty desperate situation and down to about 400 brothers, if they can harvest both seed after 10 years they'll have 800 seeds, 760 left after the tithe is sent. If 25% fails then that's 570 newly implanted brothers, bringing them up to 970 brothers (most of which are scouts admittedly). I mean there's a lot more going on, the failure rate could be a lot higher, they might not be able to train the scouts or equip them as brothers but still, that's only 10 years. In 20 years the Crimson Fists could go from 128 to a healthy 750.

I think we need one of the resident fluff masters to clear this up.

Many things a chapter does are part of bargains or treaties. In the case above, where a chapter is facing extinction they can at any time forego their agreements, obviously with the understanding they will have to deal with the consequences at a later time. Better to live and pay a fine than comply and die?

Unfortunately I don't have a source, but I'm almost positive with what I understand about the progenoids.

Two of them, one in the neck, one in the chest. The one in the neck matures in 5 years and is removed beforehand. The one in the chest takes 10 years to mature. However, a marine needs his progenoids to function as it regulates the mechanisms of all of the other implants. But he only needs one of them. That's why a marine who lives to 5 years has effectively guaranteed a replacement for himself. Since at least a good chunk of that time, a marine will be a scout for, by the time a marine has his black carapace, he's probably only got a year or so before his neck progenoid can be removed. A marine who lives 10 years has his chest progenoid removed, but doing so will kill him, which is why it's removed on the battlefield.

These progenoids are not replaced.

That's great, and believable. Can you find the source for it, so we can clear it up around the table, though? 'A bloke on the Internet said...' doesn't cut too much ice!

I would like to point out that, if marines have their progenoids removed after they mature, there is little point to the reductor wargear, which is designed for extracting progenoids on the battlefield.