meiotic

A counterexample is meiotic drive, where alleles disrupt the meiotic process in order to favour their own transmission, even if the alleles in question ultimately produce a less fit organism.

The article discusses genetic post-meiotic changes that propagate differentially through the body.

Which of selection or variation does meiotic drive fall under?

Same goes for methyl and acetyl markers, transcription factors, nutrients, toxins, and whatever else comes along for the ride in the meiotic cell.

Suppose a whole chromosome is, on average, likely to undergo one cross-over every time a sperm or egg is made by meiotic division, and this cross-over can happen anywhere along its length.

Biologists were doing genetics, working out the rules of heredity, mapping genes onto chromosomes, understanding meiotic cross-over, for decades before the physical nature of the gene was understood.

The only way you could determine the genetic content of a single sperm would be to isolate it's 3 meiotic sisters, determine their content, and then assume that the remaining spermatozoan contained what was left.

If the genetic unit we are considering is only 1 per cent of the length of the chromosome, we can assume that it has only a 1 per cent chance of being split in any one meiotic division.

Somatic mosaicism is well known to occur in normal germline cells as the process of meiotic recombination and in cells of the immune system within Ig and T-cell receptor genes as a result of V(D)J recombination that provides diversity in immune responses.

While I’m of the opinion that trans-generational epigenetic inheritance is not typically important in human biology, the most convincing argument I’ve heard is that the egg cells that will become a grandchild are present and post-meiotic in the fetus of the mother, so exposures to the grandmother could have effects 2 generations down without requiring some relatively exotic pattern of inheritance.

Meiotic drive is not Darinian selection, but it is selection.

Meiotic drive can effect which embryo's survive [1] & [2].