How would that effect games? Would there be more "Saving Private Ryan" type adventures?
Would games like Pendragon with multi-generation play be more common?

What do you mean if it was recessive? >_>

From a purely genetic perspective you'd have fewer people with leadership qualities out there, and therefore fewer people qualified to lead. Depending on just how many attributes this "leadership gene" was responsible for you might have anything from a world mostly full of pretty passive people to a world full of incompetent leaders to a weird backwater world where those most qualified to lead were identified early and given positions of power befitting their enhanced genetic state. It's anyone's guess, really, since it depends on a lot of societal structures that I can't predict without further study.

Having never seen SPR and never played Pendragon, I cannot comment on either.

I would argue that, by definition, something akin to 'leadership' is already an existing construct (in genetic terms) falling under the 'fight or flight' category.  Being recessive would simply mean that a fewer than average number of people would have an innate desire/ability/mentality for 'leadership'.  Factor in the SPR aspect (dying as something a leader does) and it becomes even less of a factor as those genes are removed.

I think the main problem with this line of thought is that leadership is a fairly complex trait.

Traits are usually the product of natural selection, and therefore evolve according to the needs of the species within which they are found. We evolved the leadership gene because we are social animals, designed to work together in families, groups, societies, which in turn requires an adequate hierarchy, which in turn requires humans who are naturally predisposed to acting as leaders and humans who are naturally predisposed to acting as followers.

Now, genes as we know them are far more simple than we make them out to be. At its core, our DNA is merely a user manual, designed to create proteins, chemicals which can act as signals, hormones, or other such things. The hard to understand part of genetics is that, in order to overcome the inherent simplicity of the way our genes code information, they interact with one another and influence each other in a myriad of different ways.

The concepts of dominant and recessive are ones you will only find in things that are manipulated by a single gene, such as the shape of your ear, your eye color, etc. However, more complex traits, such as height, intelligence and leadership are defined by multiple genes, all of which play their part in modulating, stimulating or inhibiting the desired trait, which is why we have people who can never lead, people who could lead in certain circumstances, natural-born leaders, and even people who can eventually learn how to lead if given enough time.

So, to answer your question, turning leadership into a rarely expressed trait can have such a dramatic effect on humanity that we might not have been able to survive past the Ice Age, let alone reach the level of development and knowledge we have today, though this depends on how 'rare' you want this trait to become, and over what period of time. Slowly fazing the trait out over multiple generations might adapt human society into something different, while suddenly removing it in only one or two generations could lead to our society's destabilization and downfall.

My point was increasing the importance of "Bloodlines" to the level it was historically or higher.
Arranging marriages, ensuring the survival of heirs, maintaining families, that sort of thing.

In reply to GreenTongue (msg # 5):

You're asking would develop if people held intrinsic traits that made them vital to the functioning of society?

In Eberron, there are the dragonmarked houses, which maintain commercial dynasties in part because some of their members are inherently better at certain useful things, like crafting, or controlling weather. In that setting there was a huge war that saw the deaths of many of the imbued individuals, which could be reasonably expected to strain the human and demi-human resources of those houses, weakening their holds. Surviving members of the families, even those without marks themselves, would be sought after and protected and kidnapped and blackmailed, etc. Those who got on the wrong side of the law would be bailed out and given leeway.

PCs can be marked themselves and suffer complications due to this status, or the party could be employed to help or hinder a dragonmarked house in its time of desperation.

Is that the kind of thing you mean?

In reply to engine (msg # 6):

Yes. That sort of things.

In reply to GreenTongue (msg # 7):

Cool, then. I don't know that I'd personally enjoy a multi-generational game, but I dig the idea of seeing how different houses would rise and fall in influence as a result of crucial heirs dying, being lost, getting married, etc.

In reply to GreenTongue (msg # 5):

Funny thing about that is, while the bloodlines were held in high regard, being part of one didn't necessarily make for great leadership.  It could be argued that a great many, if not most, royal bloodlines built their reputation off the actions of a few outstanding individuals...while much of the rest of the bloodline was of dubious leadership value.  I mean, technically speaking, to the best of my knowledge the same bloodline produced England's King George III (who was, according to many historians, at least somewhat insane and arguably a poor leader) and Queen Victoria, who is still heralded to this day as one of the greatest monarchs of history.

So, it's more a question of sustaining and enhancing the family reputation than it is of any genetic advantage, historically speaking.  Most of the arranged royal marriages of note in history happened not because the mated pair had a good chance of producing strong leaders in their children, but because the families saw advantages to be gained by connecting to each other, most often political or monetary, rather than genetic.

(There's also the question of what, exactly, makes for good leadership, and under what circumstances, as a good wartime leader does not necessarily make a good peacetime leader...but that's an entirely tangential debate to your question.)

In reply to facemaker329 (msg # 9):

Well, the quandary is if there was a genetic relationship and it being recessive explained how some in the same family had it while others didn't and why "breeding" has an importance.

Obviously there are those in the "real world" that believe it but my thought was what if it was true?

Would there be "Super Leaders"? Would there be powerful organizations that controlled the information about bloodlines?
Those that wanted to control the mixing of them?
How would people act if they believed that only the select few actually should be their leaders.
What of the random mutation that gave leadership outside of the established lines?

I feel like there have been fantasy movies that touch on these exact questions. Not that there can't be other answers to them.

That would be interesting if a) the world didn't have a concept for "random mutation," and b) if the powers of "leadership" were impressive, but either not impossible to fake or not impossible to bring about by normal methods of loyalty and intelligence.

If they don't understand "mutation," they might have an idea that "the gods" sometimes bring in a new element. Some might see this as a result of the establishment becoming corrupt or wasting their gifts, and would support the mutant. Others might then see it as a test by the gods, and support the old leaders.

If the powers could be faked or be achieved by mundane means, the true leaders (if they wanted to retain their hold) would have to reassert that their power was still special in some way. In Eberron, others could effectively accomplish (or seem to accomplish) almost everything a dragonmarked heir can accomplish. The additional effort would dissuade most people from bothering, but if people were unhappy enough with the houses, they might rely on a self-made upstart, which would threaten the house monopolies, spurring conflict.