Why does incest result in birth defects?
Why does incest result in birth defects?
Just to be well and truly fuckin clear. I am not now nor have I ever been nor will I ever be contemplating shagging a family member.
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Human genes only really "work as intended" when they are combined from very different sets.
So-called "recessive" genes are overruled by your partner's different pile of genes. They are usually shit traits like soggy bones or hair growing backwards, but since they never dominate, they haven't been naturally selected away. They're just harmless baggage.
You can still get them because it's all random, but the likelihood is generally low.
If you don't have that difference in mating genes, more of these recessive genes get to have a say in building the human. This severely increases the likelihood of birth defects.
https://en.wikipedia.org/wiki/Inbreeding
Fun fact: This is one of the reasons why - when we start colonies on the Moon or Mars or wherever - it's important that we send a fuck ton of people.
Well, there’s a new insult: “You soggy-bones looking mother fucker.”
That just reminded me of the only community I really miss from reddit, r/neverbrokeabone. Lemmy just doesn't have the number of users to support such a niche community.
But yeah, there were all sorts of good insults there for when people broke a bone. "Soggy-bones mother fucker" would have fit right in.
It's 4 in the morning and I'm sick, got them albuterol inhaler shakes, and "soggy bones" made me laugh so hard I went into a coughing fit.
It was backwards hair that did it for me.
Or a fuck ton of, samples.
So, note for any women looking to colonize Mars, your womb will belong to the colony.
In any long term colony, with hard constrained resources, a lot of individual rights will have to fall below the collective requirements. The collective needs will have to supercede the individual. It's a classic "Tragedy of the commons" situation, otherwise.
Mandatory pregnancy is likely not one of them however. More likely mandatory birth control, with all pregnancies being planned. There will also likely be strong incentives to widen the gene pool.
E.g. A couple might be allowed 1 child by default, with additional requiring either that they already have a useful level of general diversity, or that doner eggs or sperm are used.
Even simple financial incentives could achieve the same effects, if done right.
Those of you women living in U.S. red states will be familiar with the feeling.
Not necessarily true. Presumably there would be a terms of service you'd know about before takeoff. And any of it could easily be voluntary rather than mandatory.
Yes. Nonetheless, I'd like to direct you to watch a scene in the series It's always sunny in Philadelphia named "the implication" and try to apply it to Mars.
Each person sent costs a fuckton of fuel. Do you think they’d waste it on someone who will not contribute to expanding the population?
That was the point. It can be like voluntarily giving up rights by joining the armed services.
Then science better get going on artificial, external wombs. A lot of people would be overjoyed to be able to have kids without the physical risk of pregnancy, and the technology seems like it'd be mandatory for true colonization efforts
Ok, but why are recessive genes necessarily bad?
Or, they probably aren't, but it turns out when you activate them you get more bads than the goods. Why is that?
Good question!
They aren't necessarily bad as such, just "random and unfiltered".
Dominant genes get "battle tested" all the time, by definition. The harmful ones are likely to result in a human that can't survive or have children, while the good ones remain.
Recessive isn't always bad. In fact, many (maybe all) genetic traits have a dominant and a recessive information.
For example peas. Let's say there is a gene for colour. The dominant variation of the colour gene carries the information "green". Let's call this gene c for colour. Then there is a recessive variation with the information yellow.
We'll write the dominant information as capital C and the recessive as lowercase c.
Now there is a pea with the genetic information CC (one from each parent). That's a green pea.
Then there is one with Cc (father green, mother yellow). But you see the pea and it looks just like a green pea. Because the green gene C is dominant and the yellow c is recessive. You don't know, that this is a mixed variety.
If two seemingly green peas pollinate each other, but under the hood, they are Cc, then they might produce a cc yellow pea.
For a lot of genetic information that's not a problem, they are just different characteristics and not harmful.
But if you have B = your blood coagulates normally, and b = your blood doesn't thicken, you just bleed out and die when you have a paper cut...
Then inheriting b from both of your parents is a terrible fate.
This happened in the House of Saxe-Cobourg and other nobility in the 19th century.Edit: the last part is actually a bit more complicated, but the explanation of dominant and recessive still works.
For mars, they could do whole-genome sequencing and select for people with fewest deviations from the de facto wild-type human genome.
That sounds unsettlingly like eugenics.
Yea but Mars is not the right place to just wing it.
I don't know that I agree. Or rather, I agree, but come to the opposite conclusion.
I think that as we take our first steps into the broader universe, we have to consider the ethics and morality that we're stepping out with. If we choose people based on (let's face it) arbitrary genetic variation, independent of their ability to perform the tasks assigned or their representative value to the human race as a whole, that means that as we plant our flag on the Martian soil, we'll be taking eugenics with us.
The minimum viable population of a species is about 50. In order to prevent genetic drift over time you need closer to 500, but we're sapient; we can implement genetic therapies when needed to help maintain allele frequency while the population is growing. And, in reality, operating a long-term Martian colony is probably going to need more than 50 people anyway; a recent NASA study suggested 25 would be enough, but previous research said 100+ would be necessary.
And keep in mind, an actual Martian colony doesn't have to be self-sustaining in a complete vacuum (ha) for centuries. It will probably be only a generation or two before regular travel between the two planets will be possible. Plus, if we build and maintain a lunar colony first, the initial population of a Martian colony can be much larger.
In short, I think I'd rather work harder and send more people so that we can ensure we're maintaining our values, than allow such a retrograde idea as eugenics to poison our first venture toward being a multi-planet species.