FWIW, All You Zombies has been adapted into a movie called Predestination. I haven’t read the story but the I thought the movie was pretty good. It apparently adds a bit to the short story but preserves the underlying structure pretty faithfully.
I just want to say you have a good user name for participation in this thread.
Here are my thoughts: In the single timeline time travel scenario, you still have half of your genes coming from your mom and your dad. But one of your parents will have to have half of their genes from you. Assuming they give that half back to you, then the other parent would also have to have half your genes.
So unless you went back and got both your grandmothers pregnant, I’d be looking into how closely related your parents really are.
Too closely matched to be devoid of the problems of incest? I think you lost your train of thought. Too many double negatives, perhaps. The problems of incest are precisely because of being too closely matched. What you’re asking for is being distant enough to be devoid of problems, or close enough matched to start causing problems. Or something.
Technically, that’s impossible to know, as any baby has a risk of being genetically deficient. We can answer the question statistically, but not absolutely.
Each grandparent contributes to each grandchild independently. PgF and PgM give rise to Daddy and Uncle*. MgF and MgM give rise to Mommy. Auntie’s parents are some other couple.
Daddy and Uncle share 50% consanguinity. Uncle’s kiddoes get 1/4 from PgF and 1/4 from PgM. You get 1/4 from PgF and 1/4 from PgM.
Because what’s the point of time travel incest if not to make it self-ancestoring?
I think you’re talking about the aforementioned Time for the Stars, where the hero returns from space travel to marry his great grandniece from his twin brother.
Transgender partner? You lost me.
Um, what? 1/3 of your grandmother’s genes, or 1/7 of her genes?
Of course, by the time Lorelei and Lapis show up, it is well in the future, and one can surmise that (a) birth control is a strong science; (b) any breeding can be genetically monitored/tweaked after conception. In which case, sex with his clones is as risky as masturbation.
Erm, what?
I think that is indeed what he said. Too closely matched to not start having inbreeding problems.
Also, I too would like to know what the thing about Bill Gates wanting to kill 95% of the world was about.
I guess the double negatives got me.
Erm, Watch Bill Gates’ Ted Talk, where he talks about depopulation of the earth using vaccines.
Somehow I feel you’ve misunderstood something.
Here’s a quote from Bill Gates after being asked a question from Sanjay Gupta…
To me it seems like Mr. Gates is talking out of both sides of his mouth and trying not to let on to something deeper.
He says he wants to reduce disease caused childhood deaths by half, putting those children into eventually adulthood and procreating, yet in the same sentence he says he wants to reduce population growth.
The rate of growth of population in western world is already reduced to a level that cannot be recovered from. This is from purely a capitalist viewpoint, Capitalism cannot be sustained the way it has been for the last 80 or so years without grown of population at a certain rate. Bill, being one of the biggest capitalists I can think of double talking like this just sounds too shady to me.
Dr. Sanjay Gupta: Ten billion dollars [pledged] over the next 10 years to make it “the year of the vaccines.” What does that mean exactly?
Bill Gates: Over this decade, we believe unbelievable progress can be made, in both inventing new vaccines and making sure they get out to all the children who need them. We could cut the number of children who die every year from about 9 million to half of that, if we have success on it. We have to do three things in parallel: Eradicate the few that fit that profile — ringworm and polio; get the coverage up for the vaccines we have; and then invent the vaccines — and we only need about six or seven more — and then you would have all the tools to reduce childhood death, reduce population growth, and everything — the stability, the environment — benefits from that.
Moderator Note
This is getting well off track with regard to the questions posed in the OP. Let’s stick to the questions raised there. If you want to discuss this, please open a new thread in Great Debates.
Colibri
General Questions Moderator
Andy Libby, who was LL’s sidekick for the first novel (Methuselah’s Children? The one where they stole the starship) got eaten by a grue. In the process of reviving & regenerating him, they asked him a bunch of questions about whether or not he’d like to be brought back to life, including how he’d like to come back, and he said he’d like to come back as a woman. Who just happened to be an identical twin for the vivacious daughter of the mathematician in The Number of The Beast, also a phenomenal mathematician (like Andy). Since the TG Libby wasn’t the father (Jacob?)'s actual daughter, they were able to have sex and procreate so he didn’t really have a child with his daughter.
Man, those later Heinlein novels were kinda bent…
surely it would cause a feedback loop until johnny is 100% his grandmother’s genes?
You are correct. Sorry for the misstatement. Your coefficient of relationship is 50% with parents and full sibs, 25% with grandparents and grandchildren, and 12.5% with first cousins.
If you look at the passage of time as a characteristic unique to each particle and unrelated to all nearby particles, I think you get an interesting perspective on the idea of time travel. I don’t think it’s so far-fetched of an idea- it follows the current theories about how time dilates for particles. The illusion that their are “timelines” is created because all the particles that we observe happen to move through time at the same rate. In a universe that behaves like this, time is like a stream of three dimensional particles moving along a time axis. Rather than changing position as they travel though, you could imagine that each particle is actually extended forward to the end of time and backward to the beginning. These particles exist at each instant of time from it’s creation until it’s end and interact with each other accordingly, based on their relative positions at each instance. The events and interactions of these particles are determined instantaneously at this perspective- we’re outside of time. If a section of the particles jumped out of its local cluster at some point- changing its rate of time that it had maintained thus far and away from the other particles, (this section is our time traveler) it might be able to loop back and interact with nearby particles at an earlier time instant. Because we’re outside of time, this isn’t a sudden event- viewing particles like this would always have shown that loop back, if “always” is even a way to describe it- again, there is no time here. Anyway, the physical and chemical interactions that these particles may have with these earlier particles are normal- they impact their behavior and affect how they operate but they don’t change anything about the existence of the particle group at all- as from the time-based perspective of the time traveler, every event that occurs in the past (even though it may be the traveler’s “future”) has already happened and evaluated at the time of departure. In essence, if you will eventually go back and become your own progenitor, you would have been born as such before ever knowing that you’d go back in time. Additionally, it would be impossible to change anything about the timeline by travelling back in time- any and every action you took would only lead to the same result. This doesn’t mean humans don’t have free will, in a way. It shouldn’t be taken as saying that everything is predetermined- it’s more like every decision that any person will ever make or has ever made evaluates simultaneously. Being locked in a perspective in which time events happen consecutively instead of simultaneously just means you have to wait to find out what you chose to do.
As for how this pertains to the original questions, it may sound confusing. Since there is no external source for the genes from the grandparent you would otherwise have (and there never was), I did a few simple calculations and I’ve come up with this result: you’d have 33% of your DNA from each of your grandparents. My calculations were: let your DNA be represented by “y”. Let your father’s (your son’s) DNA be represented by “x”. Let your father’s mother’s DNA be represented by “z”. Let your other two grandparents’ DNA be represented by “u” and “v”.
y = x/2 + u/4 + v/4 (this is a rough approximation of the split of genes, the x/2 is your father’s contribution, the u and v are your mother’s)
x = z/2 + y/2 (this represents your father as the son of your grandmother and you)
therefore, y = (z/2 + y/2)/2 + u/4 + v/4
y = z/4 + y/4 + u/4 + v/4
3y/4 = z/4 + u/4 + v/4
y = z/3 + u/3 + v/3
This should correctly allow your father to be your son without any nastiness with genes coming from nowhere. You’d probably be pretty odd looking, but your dad gets a bit of a shorter stick I believe:
x = z/2 + (z/3 + u/3 + v/3)/2
x = 2z/3 + u/6 + v/6
66% of your father’s DNA is his mothers, with the remainder coming from the parents of his future wife. A little odd, but that’s the result.
As for the second part of your question, it is certainly possible that your decedent could have no trace of your genes. I’ve been using the average distribution of genes above, but its entirely possible (however improbable) that your own grandchild could share none of your genes, if your child between contributed only the genes of his or her other parent to the child. As the average fraction of your genes that the child possesses gets smaller, the probability that a decedent will be unrelated to you increases. It’s also [technically] possible that your great-great-great-great-great-great-great-grandchild could share half of your genes.
Ran out of edit time, I forgot to change the “shorter stick” metaphor. You and your father both have 66% of your DNA from your respective mothers.
The correct answer here is that Johnny is a twisted sexual deviant.
Well…he did do the nasty in the past-y
From Genealogy Magazine, 2007:
“I’m My Own Grandpa” – Where Did the Tale Begin?
James Pylant
“Now, many years ago when I was twenty-three,
I was married to widow who was pretty as can be;
This widow had a grown-up daughter, who had hair of red,
My father fell in love with her and soon they too were wed”
I don’t recall any of that. Which novel did it occur in?
Most of that was from Number of the Beast, though it continued in The Cat who Walks through Walls and To Sail Beyond the Sunset.