Editing Gene-seed (section)

===No Known Mutations===
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==== Dark Angels (I Legion) ====
{{Main|Dark Angels}}
No defects, unless you consider their <s>rampant paranoia and secrecy</s> STAUNCH LOYALTY AND HONOUR as such. Ties with Ultramarines for "most stable source", so the limited number of Dark Angels successors is usually put down as the [[Inquisition]]'s limited knowledge of the [[Fallen Angels]]. That and the fact that due to successor chapters often working with/take orders from the Dark Angels has lead to the Inquisition to fear the Angels and successors to be <s>"[[Astral Claws|legion building]]"</s> THE MOST LOYAL CHAPTERS DUE TO THE PURITY OF THEIR GENE SEED. Although that would be more credible if they had ever been anything less than a Legion.

==== Iron Hands (X Legion) ====
{{Main|Iron Hands}}
* ''No defects.''
* Noted predilection towards machinery and a disdain towards flesh.

And just to make sure, if there are any, they follow the Bible's advice on offending organs and replace them with holy machinery instead. Would probably be a very desirable source for new chapters if not for the absolute devastation they suffered in the [[Drop Site Massacre]] leaving them barely recovered millennia later and needing all the gene-seed they can get for themselves. Because, you know, even though there has been more than enough time for more than twenty other foundings of whole, brand new chapters, and some of those foundings likely making new foundings of their own, the Iron Hands still haven't had enough time. It also doesn't help how they tend to be total pricks at times. [[Nova Terra Interregnum|Or to have internal disagreements on policy so hard]] [[FAIL|'resolving' them]] [[Sons of Medusa|had Chapter-splitting consequences]]. which does not help building up Marines/gene-seed reserves, and gets you overlooked even more when the Mechanicus is deciding on whose reserves to use for the next Founding.

Alternate take: You need causalities that don't destroy the body entirely to harvest geneseed, or you need to implant it into clones, both of which are unlikely for a chapter that uses augmentations with power supplies that explode like melta bomb and that abhors even the organic parts of their own servitors. No new gene-seed, no new mutations.

==== World Eaters (XII Legion) ====
{{Main|World Eaters}}
I know what you're thinking, but it's caused by an additional cybernetic implant - the ''Butcher's Nails'' - rather than anything in the gene-seed itself. While not ''technically'' part of their gene-seed, it has been carried on as a tradition by all the "successors" that resulted from the Legion's fracturing after the [[Battle of Skalathrax]]. Hell, they were known to be total bros before all the trouble with nails. And now they are little more than [[Kharn|Teamkilling Fucktards]].

Khorne might have given them one blessing though, a sort of extra lives cheat code… But they are limited and are only earned by participating in the arenas.

==== Ultramarines (XIII Legion) ====
{{Main|Ultramarines}}
*''No official defects.'' Considered the most stable and preferred source of gene-seed for new Foundings. Possible predilection towards conformism and communitarianism.
**Due to a lack of any real interesting or identifying traits in and of itself, discussions for reclassifying the Ultramarine gene-seed from the most stable source to the most generic source were in the works. These talks were surreptitiously shut down by [[Who Watches Them|Inquisitor Warden]] for offending his sensibilities.
**Also worth noting is that the Ultramarines, in one of their bro-iest moves, "adopted" a fair number of loyalists from traitor legions after the heresy and are heavily implied to have taken in members of the two missing legions after whatever it was that got them disbanded. There is no real way of telling if an Ultramarines "successor" might be from the relatively stable stock of World Eaters or Iron Warriors. In most cases only a single high-ranking [[Belisarius Cawl|archmagos]] knows the truth, so even the chapter itself (except possibly the command and the eldest brothers) is in the dark about its history.

==== Death Guard (XIV Legion) ====
{{Main|Death Guard}}
*Emphasis here is on ''known'' mutations - there's no actual evidence of Death Guard gene-seed having any problems at all, because we've never gotten any fluff covering any attempts to use the gene-seed from a Death Guard, even though one would assume that by now they'd have the most fucked up Progenoids of any Legion.

During the [[Great Crusade]], the Death Guard had a much stronger constitution than most Legions, leading to their role as the toxic environment specialists. Post-heresy, however, the Death Guard are so diseased that implanting Aspirants seems more or less impossible - however, there have been new Death Guard legionaries who are not defectors from other Legions or renegade Chapters, apparently made with the gene-seed reclaimed by the [[Plague Surgeon]]s. How it functions still, no one knows, though we suspect it has more to do with [[Nurgle]] infectiousness than with the progenoids themselves.

The most overwhelmingly likely explanation is, however, the Death Guard simply jacking loyalist gene-seed from fallen loyalist astartes and loyalist gene-seed stockpiles and using it to create new recruits, as '''every single Traitor Legion with tainted, unusable geneseed does this.''' As per LoS, appears to be a mixture of both, likely depending individually on each Death Guard members level of disease and mutation, supplemented by stolen and possibly altered loyalist gene-seed (see Plague Surgeon).

==== Alpha Legion (XX Legion) ====
{{Main|Alpha Legion}}
<s>No such Legion exists, therefore no such gene-seed exists.</s>
*Were you really expecting ''known'' mutations, or anything else, from this Legion???

In all seriousness; like much of the Alpha Legion, we don't know all that much about their gene-seed. Whatever idiosyncrasies or flaws they have are kept under very tight lock and key. And with their nature of running as individual operatives in and out of the [[Eye of Terror]], to what degree their gene-seed is tainted by the Warp or other means varies from Marine to Marine. Though their knack for secrecy, paranoia, and tendency to subvert the enemy instead of direct combat is probably a notable trait. Outside of occasional Warp-corruption, we ''assume'' it's possibly one of the most stable gene-seeds, probably as much as the Imperial Fists or Night Lords. Something of note; they often use any mutations that they have as a scare tactic, hiding them and then revealing them on the battlefield in order to shock the opponent.
They also use hypnosis and deep-indoctrination more than other chapters, so they may have an altered sus-an and/or catelapsean.
Sometimes it's implied they all look alike (like Alpharius) but sometimes this is said to be due to ''surgical'' alterations, but it could be that the gene-seed does more to alter their appearance than normal, like the Sons of Horus and this is further supplemented by surgery. It's also said that some Alpha Legionnaires tended to be noticeably taller than most Space Marines, large enough to pose as either [[Alpharius]] or [[Omegon]]. This, combined with their unusually short Primarchs and their tendency to look alike, seems to suggest that this was intentional, either by the Legion themselves picking only notably large aspirants or by the Emperor fully leaning into the Legion's whole "smoke and mirrors" theme.