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Marvel Comics' Celestials in the 1983 OHOTMU handbook

Leon Genetic Sequence – aging in the Marvel Universe


The León Genetic Sequence (LGS) is a No-Prize HypothesisA made-up explanation to plug a plot hole. to explain how time passes in the Marvel Universe.

First, let’s review he problem.


Why ?

The Marvel Universe stories have been running since, at the very latest, 1961. This makes the longevity of most recurring characters wildly improbable

The official solution is a “sliding” 10-year timeline solution. In this framework, the Fantastic Four’s fateful flight is always, retroactively, 10 or 13 years ago (depending on versions). So as of 2023, it didn’t take place back in 1961 – at most, it happened in 2010

And thus everything in modern Marvel stories retroactively happened between 2010 and 2023. Until 2024, when it will retroactively have happened between 2011 and 2024.


When using this “sliding” 10-or13-year timeline, issues abound for characters with clear ties with historical events.

For instance :

Thus, using this approach, you end up having to forever, constantly rewrite all these ties Some Marvel examples :

  1. RetconningMaking changes to a character or story after the fact. Tony Stark as having built his suit in Afghanistan, not Việt Nam (like in the Iron Man movie).
  2. Retconning the Punisher as having served during Desert Storm, not in Việt Nam. Which doesn’t carry the same historical charge.
  3. Retconning the Black Widow (Natalia Romanova) as an high-tech industrial espionage expert rather than as a Cold War KGB legend.

Homey don’t play that

Obviously, writeups.org cannot work that way.

Especially since we do in-depths profiles. hich often means clarifying historical, political, social and cultural references that play a role in the character’s biography, characterisation, appearance, etc..

For instance, our profile for Captain Marvel (Carol Danvers) has a lot of stuff about what it meant to be a female military pilot back then, the context for her intelligence and special ops career, her fascination with sci-fi and the US space program, etc..

Carol Danvers (Earliest) (Marvel Comics)

Carol Danvers is a good example of a character where the question “how old is she, so we can better understand this character’s past ?” becomes a recondite matterSomething obscure and complicated. This wording is a reference to HG Wells’ The Time Traveller..

What ?

The León Genetic Sequence explanation takes another approach. It allows the events to unfold much like in the comics as published, without having time perpetually slide.

The trick is simple. The protagonists do not age.

This approach has been occasionally used in the comics. For instance :

  • Nick Fury’s aging has been receiving Infinity Formula injections ever since the 1940s. And therefore aged little since his World War Two salad days.
  • Jimmy Woo’s body and mind were, in 2006, recreated in the state they were in in 1959.
  • The Black Widow (Natalia Romanova) received the Kudrin treatment, making her age even slower than Nick Fury.
  • Magneto (Max Eisenhardt) had a large chunk of his physical aging erased by Alpha the Ultimate Mutant.
  • The mutants modified by the Weapon X program, such as Wolverine (James Howlett), received a potent age suppression factor.

The postulate behind the León Genetic Sequence is that age suppression factors are actually carried by many humans and mutants. And the explanation for this lies in the distant past of humanity.

Enter the Celestials

One feature of the Marvel Universe are the Celestials. These alien space gods exist on a cosmic level and guide the evolution of life and the universe.

The Celestials engineered the human race along two main lines :

  • The creation of an Eternal and of a Deviant subrace.
    • Eternals are near-perfect immortals able to tap cosmic energy.
    • Deviants have an incredible rate of mutation, making each child completely different from their parents.
  • Adding an extraordinary potential for super-powers, sometimes called the X-Factor Genetic Sequence. Though others species have Eternal and Deviant subspecies, the x-factor in Humans seems to have been uniquely successful.
    • If powers emerge spontaneously, often at puberty, the person is called a mutant. Like the X-Men.
    • If powers are triggered via exposure to exotic factors, the person is called a mutate. Like the Fantastic Four.

In this article, we postulate that the León Genetic Sequence is a part of the second manipulation. It carries the potential for an extended lifespan and greatly slowed aging once they reach full adulthood.

Just like the X-Factor, this sequence remains unexpressed in the vast majority of the population.

Namor the Submariner - Marvel Comics - Alex Ross poster art

Namor is, off the top of me head, the earliest example of having to find a narrative device to explain why a 1940s Marvel Universe character was still in his prime during the modern age of super-heroes.

How ?

The León Genetic Sequence (LGS), when expressed, has several effects :

  • The natural life expectancy of the person becomes normally distributed around a mean of 121 years, with a standard deviation of 10 years.
  • The aging of the person drastically slows down during their 20s. Some, like Peter Parker, experience this as early as 17. The slowing effect is usually a factor of 3 or 4.
  • The odds of spontaneous expression normally are 1 out of 200,000. But it seems active in more than 80% of superhuman or borderline superhuman mutants and mutates.
    It is thought that the X-Factor and the LGS sequences are intended by the Celestials to work together.
  • 34% of the bearers of the LGS will have blue eyes or eyes with a noticeable tinge of blue. Even if their ethnicity should make this much rarer (e.g., most African and Asian ethnicities).

(The last one is a tiny joke about odd colouring choices that were common in Silver AgeSuper-hero comics from the late 1950s to the early 1970s. super-hero comic books).

The name “León Genetic Sequence” is an oversimplification. It’s not actually a single sequence. But the name has endured since its exact nature remains elusive.

More effects

  • LGS bearers associate with each other more than they statistically should. There might be subtle cues, perhaps pheromonal, that are subconsciously picked up by other LGS bearers.
  • This might be a genetic engineering feature to enhance some aspect of reproduction. However, it doesn’t seem gender-sensitive. So maybe not.
  • Two LGS bearers will not necessarily produce a LGS-active child, though the chances seem greatly increased.
  • However, the fertility of all LGS bearers seems well below the Human average. This may be deliberate design, to keep the proportion of LGS-positive persons in the population at a certain level.
  • Most persons with an expressed LGS sequence will have remarkable — but not usually superhuman — abilities to withstand many diseases and recover from physical trauma.
  • The large majority of LGS bearers present a conventionally attractive physique. See our height and weight of super-heroes for more about this.
  • This seems related to the manner many superhumans deploy impossible energies without major, visible physical alterations.

(The proposed LGS idea doubles as a rationalisation for many older narrative and aesthetic conventions in American super-hero stories. It’s a variant over the “one impossible thing” writing guideline. Namely, if we introduce something weird like the LGS, we might as well use it to lower suspension of disbelief about other, somewhat weird/stylised bits in the stories).

Even more effects

  • Those an expressed LGS sequence retain their childhood ability to absorb vast amount of new information. This is believed to be related to their excellent healing abilities.
  • In practice, it has been observed that LGS bearers tended :
    • To explore more areas outside of their academic specialties. This makes scientists, in particular, unusually multi-talented.
    • To be more curious and inclined toward exploration of the unknown.
    • To be more likely to remain in a school environment for much longer than the average.
  • Many subjects also demonstrate below-average emotional maturity, which might be tied to this mental plasticity.
  • Another psychological aspect is that LGS-active persons are more likely to see themselves as persons of destiny. And therefore to seek greater-than-life deeds and imagery, as well as enter dangerous situations.


When ?

The León Genetic Sequence has been around since the First Host of the Celestials, roughly one million years ago.

Mutants and mutates seem to have become more numerous since the 1940s. By contrast, the percentage of active LGS bearers seems to have been relatively stable since the First Host.

That some people remain young for ages is thus well-established on Earth-616The main Marvel Comics version of Earth.. People have known for ages that some lucky few hit that jackpot.

So it’s not seen as different from, say, naturally having a great singing voice. Or some XXth Century pop stars such as David Bowie or Dick Clark having been oddly unaging.

The reverence for youthful, fit, hard bodies is also older and more widespread on Earth-616. Thus explaining why so many stories set in different places and times display modern US sensibilities about such.

Starman (Ted Knight) (DC Comics) talks about Iran Karkull and aging

The temporal energy from Ian Karkull was a notable, early-ish DC Comics narrative device to have notable 1940s character age little over decades.

Whither DC ?

The DCU doesn’t have convenient genetic engineers space gods. And it generally puts less of an emphasis on genetics as the go-to explanation, with the exception of the metagene.

Still, some GMs might wish to use the LGS in their DC campaign. Once this decision has been taken, there are numerous possible source for an LGS-like phenomenon.

Random ideas include :

  • The first pass of the Godwave is the simplest approach. With “long youth” humans appearing as the gods do.
  • The Ian Karkull incident, which altered the aging of many JSA members, might have echoed up and down the timeline. If so it changed reality to add people with LGS-like characteristics in the entire past, present and future.
  • It might have occurred during the Crisis on Infinite Earths, and then have become part of the New Earth’s history.
    Perhaps the death of the Immortal Man occurred differently. Perhaps he deliberately sacrificed himself so that many people on the soon-to-be New Earth would be blessed with LGS-like characteristics.
  • One may want to keep the Kirby connection by invoking the Third World.
    • Perhaps an Old God of youth was killed as the Third World gave way to the Fourth had their essence scattered on Earth.
    • Perhaps the LGS is actually a sort of anti-Anti-Life Equation, granting superior free spirit, non-conformity, youth and vitality to those happy subjects who host it in their subconscious.

But as the reality reboots accumulated in the DC Universe, the matter became less pressing. If reality keeps being tampered with and recreated, and editorial believes that younger characters are more relatable, then the issue just drifts under the carpet.

Writeups.org writer avatar Sébastien Andrivet

By Sébastien Andrivet.

Helper(s): Roy Cowan, Frank Murdock, Adam Fuqua.