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Choosy Eggs May Pick Sperm for Their Genes, Defying Mendel’s Law

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Re: Choosy Eggs May Pick Sperm for Their Genes, Defying Mendel’s Law

#21

Post by sjg007 »

vikiomega9 wrote: post #9
cwkoss wrote: post #2

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?

These decisions interface via binding sites[1] which can be thought of as having "bias". [1] https://en.wikipedia.org/wiki/Binding_site

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.

Re: Choosy Eggs May Pick Sperm for Their Genes, Defying Mendel’s Law

#23

Post by psloth »

gowld wrote: post #6

Did they rule out the possibility that the mutant gene they put in the male mice caused the sperm to be bad at sperming?

"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"

Re: Choosy Eggs May Pick Sperm for Their Genes, Defying Mendel’s Law

#24

Post by Alex3917 »

chiefalchemist wrote: post #3

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.

Re: Choosy Eggs May Pick Sperm for Their Genes, Defying Mendel’s Law

#26

Post by gjjrfcbugxbhf »

Alex3917 wrote: post #24
chiefalchemist wrote: post #3

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…

I thought that partner incompatibility was extremely common?

Re: Choosy Eggs May Pick Sperm for Their Genes, Defying Mendel’s Law

#27

Post by mozumder »

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.

Re: Choosy Eggs May Pick Sperm for Their Genes, Defying Mendel’s Law

#29

Post by gewa »

rllin wrote: post #4

I feel like this is a misunderstanding how strict Mendelian genetics is. Most evolutionary theorists think more like physicists and do realize every trait is selectable.

This... Mendel's law is only applicable to a really small hand full of traits.

Re: Choosy Eggs May Pick Sperm for Their Genes, Defying Mendel’s Law

#30

Post by golemotron »

chiefalchemist wrote: post #3

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."

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.

[1] https://en.wikipedia.org/wiki/Age_and_female_fertility

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