I've encountered this concept before, but have not been aware of its name. Taken to its very extreme, we have pedigree collapse where a single individual occup

I've encountered this concept before, but have not been aware of its name. Taken to its very extreme, we have pedigree collapse where a single individual occupies all male spots: https://en.wikipedia.org/wiki/Y-chromosomal_Adam https://en.wikipedia.org/wiki/Y-chromosomal_Adam, and a single female occupes all female spots, https://en.wikipedia.org/wiki/Mitochondrial_Eve https://en.wikipedia.org/wiki/Mitochondrial_Eve Interestingly, these happened at different points in history.