Does this (read: could this) help explain why some couples have problems conceiving? Perhaps, at least in some cases, the egg is saying, "no way buddy."
> Perhaps, at least in some cases, the egg is saying, "no way buddy."
Assuming this is true, it would be happening in less than 1% of cases (given the prevalence of male-factor infertility and the prevalence of its known causes). So if such an ability exists, it doesn't seem to be getting used very often. Which, given the evolutionary complexity that would be required to evolve such a system, seems surprising. So my guess is that either that's not a thing, or else it exists only as a failure state of some other mechanism rather than as something that has evolved to directly confer some sort of reproductive advantage.
Just incompatibility, without the partner. Fluids pH problems are much more common than you'd think, and it has nothing to do with the partner (besides being treatable). And it's just one of the many problems that may occur, but none of them is like a partner issue because your bodies don't "match".
Yes. But if the egg is making a decision can't other parts of the process, at least in theory, be serving as gate keepers as well? Thst is, it's not just the egg being selective. Selective is baked into the recieving organism (i.e., the human female).
To me that doesn't sound too far fetched and to some extent makes perfect sense.
I haven’t looked it up but I’d say there’s anectodal evidence of couples that conceived with different partners after having trouble conceiving between them.
You cannot throw this kind of jokes around given how this subject can be hard to read for people to which it happened.
HN is a community with people of lot of different backgrounds so it's important to be careful.
Please don't speak for other people we don't need your protection.
Edit: miscarriages are incredibly common. This will/has affected people of almost all backgrounds. The culture of silence on the topic leaves you totally unprepared for it as a reality.
I've talked to people who have miscarried, and the parent post is actually a fine, lighthearted summary of the most reassuring conclusion that they came to: there was something off genetically and the potential child would have had severe health issues. I don't think it's out of place or off color in a discussion of conception.
That's quite the generalization you're making. It doesn't apply nearly to all people, especially for couples who miscarry at a very late stage in the pregnancy.
A friend of mine to who had the misfortune of this happening to him described it as the "worst thing he could ever image happening to a person" - they were mentally broken for months. So I wouldn't say this is a lighthearted comment to make, especially if you said it to them face-to-face.
Late in the pregnancy it is called a stillbirth rather than a miscarriage.
Stillbirth is rare. Miscarriage is incredibly common.
Both are painful I suspect a stillbirth far more so. The difference is that people shouldn't expect a stillbirth anymore than the death of a child - there is no need to prepare for it as a likely outcome. Meanwhile if you are intending to have more than one birth child you are more likely to experience miscarriage than not - it is better to be ready for it than have it come as a total surprise.
Apology aside, I'd like to add, I was also trying to suggest (perhaps poorly) there are times (e.g., miscarriage) when Mother Nature is actually do a positive. That is, it realizes something is off target.
Mind you, I get the couple is often guttes. But emotions aside, it's a biological positive.
While I don't like his politics, I am a proponent of Frank Luntz's "It's not what you say, it's what they hear."
I agree, on the surface my intent (from my POV) was not to offend. That said, I can see how my word / idea choice could have been better.
The apology is to acknowledge that yes I could have done better and then even if I didn't mean to offend the receiver's does still have value. Human to human, I wanted to acknowledge that.
Perhaps not very HN but I'm comfortable with that ;)
This is of course your prerogative. However, I would rather discuss this with someone who starts with a slightly off comment than not have it discussed at all.
We had this in biology in high school, don't remember the exact details but essentially some gene combinations just "don't work", and in mammals that manifests as a miscarriage.
The biggest issue in conception is the age of the mother [1]. As couples don't attempt pregnancy until later (often their mid 30s) this effect is masked as partner incompatibility.
Unlikely. As a selective mechanism its effect would be very subtle, and there are other, well-known, much stronger mechanisms that prevent conception. Age of the mother was mentioned. More generally, it’s defects in the oocyte’s ability to perform chromosome segregation or to nest in the uterine lining.
Reminds me of the CS problem: write a program which prints out its own source code.
But way more impressive. How can a cell with a single strand of DNA 'decide' which copy of a gene is a mutation? Or do eggs just bias for sperm with more genetic differences?
If I understand correctly, they see associations of alleles in the zygotes that suggest the gametes have not paired randomly.
Basically it could be that the egg and the sperm have different proteins expressed on their cellular surfaces which go together like a lock and key and may also function as attractors ( chemical sensing or something).. all of this would originate from genes in the gametes.
This is a problem I have with this sort of journalism. In the big picture, the prevalence of the effect is low, and so we do not have to throw away all of reproductive and evolutionary biology as a consequence, but that is exactly what creationists will claim.
Try saying that around a geneticist :( most i know consider mendelian genetics to apply to everything and nearly all traits/phylogenies are considered monogenic.
You hang out with the wrong geneticists. Most do not consider most traits to be monogenetic. It’s just vastly easier to focus on them when doing research. But the field as a whole has long since accepted that most interesting traits aren’t Mendelian. The whole field of GWAS and (e)QTL studies is founded around that recognition, and virtually all modern genetic models assume at least an additive effect of (known and unknown) variations as contributors to a given phenotype (and have, for a very long time).
"Perhaps, Nadeau reasoned, the problem lay in the sperm, not the egg. He therefore bred male mice with and without the mutation to healthy mutation-free females and found no differences in the males’ fertility"
This probably answers a question I have about genetics - that there just isn't enough variety if reproduction was random.
Genetic differences that have no bearing on survivability, like skin patterns or colors or whatever, should be widespread through every species, but they're not.
Skin patterns and colors do have impacts on survivability! Some species use camouflage to avoid predation, others use bright coloration to attract mates.
There's also a flaw in your premise -- reproduction is not random, it's subject to selection at a number of levels. Most selective forces act to reduce genetic diversity, both at the selected gene, and at nearby genes.
That's really interesting to think about. Somewhat related, I asked a geneticist once why there was so much diversity in humans vs pigeons which all looked the same to me.
He said, "We're tuned to notice differences between people, not pigeons. Perhaps we all look the same to them!"
Perhaps there is precisely this sort of random variation in the differences we don't notice, because by being oblivious to them they are not sexually selected for or against?
If anything, humans have abnormally _small_ genetic diversity; most species have more. We went through a population trap at some point in the past, and nearly went extinct; we probably lost most of our diversity then.
Don't be surprised if Todd Akin comes out of the woodwork to say he was right.
i.e. Mr. "It seems to be, first of all, from what I understand from doctors, it’s really rare. If it’s a legitimate rape, the female body has ways to try to shut the whole thing down."
Furthermore, if true, it shouldn't be overly surprising, since gametes are another stage in the life of an organism with great selection pressure. Why assume it behaves randomly?
this is interestingly in line with chinese traditional medicines perspective on reproduction. their theory is that it’s heavily based on the receptability of the egg and therefore it’s largely the mother who’s largely in control of things like gender selection. things like eating more acidic or basic foods affect the environment for the sperm to swim in and even the month of the mother’s life has an effect on what the egg would choose.
