Hacker News Reader

Comment by koolba | Hacker News Reader

> You'd have to be lucky, but there is a lot of time to be lucky in (seen from the point of humanity of course, not from the individual dropping in the sea).

I’m no biologist, but I think you’d need at least two people to have a chance at sustainability.

View on HN

I can't remember where I read this but I think you need at least 16 people to have a genomically sustainable population

We are going to need a bigger boat ....

I am not fetching and rereading the paper now but even simpler genomes than ours required many more individuals not to go extinct.

The Origins of Genome Complexity

Abstract Complete genomic sequences from diverse phylogenetic lineages reveal notable increases in genome complexity from prokaryotes to multicellular eukaryotes. The changes include gradual increases in gene number, resulting from the retention of duplicate genes, and more abrupt increases in the abundance of spliceosomal introns and mobile genetic elements. We argue that many of these modifications emerged passively in response to the long-term population-size reductions that accompanied increases in organism size. According to this model, much of the restructuring of eukaryotic genomes was initiated by nonadaptive processes, and this in turn provided novel substrates for the secondary evolution of phenotypic complexity by natural selection. The enormous long-term effective population sizes of prokaryotes may impose a substantial barrier to the evolution of complex genomes and morphologies.

Lynch, M., & Conery, J. S. (2003). Science, 302(5649), 1401–1404. doi:10.1126/science.1089370

There's no bright-line "minimum viable population" above the trivial answer of 2. You'll see people suggest numbers anywhere from a couple thousand down, but these don't mean that rebuilding a population is impossible, just that there will be severe effects. We've observed populations of as few as two individuals go on to become invasive, wildly successful populations when introduced to new habitats.

> We've observed populations as few as two individuals go on to become invasive, wildly successful populations

That sounds fascinating. What species?

That particular case was Pinta Island in the Galapagos, where a breeding pair of goats was introduced in 1959. The population eventually reached a peak of 41,000 before a long and ultimately successful eradication campaign eliminated them.

Reply on news.ycombinator.com