Viable population size

[Mgellis]

Non-scientist here doing some research for a story...

I know that a species needs a certain minimum population to avoid dangerous inbreeding.  I've heard different estimates, but the 500/5000 rule seems to be one experts consider reliable.

Do all of these creatures have to be currently present?  Could you, for example, have 50 individuals at any one time, but have 5,000 genetically diverse embryos in cold storage, and use artificial insemination to add new genetic material to the herd/pack/etc. every other generation or so?  You would probably have to collect new embryos every once in a while, but it would take a while to cycle through your entire supply of embryos.

Does this sound plausible?  Or is there a better way to do this?  Assume one reason for doing this is a lack of space--there is room for 50 of these animals (e.g., lions) but not 5,000 of them (i.e., a large rotating space habitat designed as a nature preserve). 

Any thoughts on this?  Thanks in advance.

 

[Sensei]

It depends on development. One smart person with genetic knowledge and equipment would be enough. Theoretically, such a being would be able to artificially differentiate the offspring through genetic modification enough to avoid genetic diseases, or to make one-to-one clones without traditional sexual reproduction..

The creation of "Eve" from the body of "Adam" or vice versa is possible even with today's technology.

Edited May 11 by Sensei

[TheVat]

46 minutes ago, Mgellis said:

know that a species needs a certain minimum population to avoid dangerous inbreeding.  I've heard different estimates, but the 500/5000 rule seems to be one experts consider reliable.

 

Well first, Franklin's RoT is 50/500, just to get our decimals in the right place, and it is highly dependent on species reproductive rate, habitat needs, average number of harmful recessive alleles (it's around 5 in humans, IIRC) and probability of disruptions to the ecosystem.  Also, an artificial one, i.e. a zoo or wildlife preserve in an O'Neill colony or what have you, would have different requirements than a natural ecosystem where the goal is to save from extinction.  Franklin et al were trying to make a RoT for wildlife conservation in natural settings, especially ones under siege from human depredations.  So the space habitats you envision might work with a lower number.  The 50 is a minimum in a locality to reduce deleterious inbreeding between close relatives, the 500 is the total number of that species in the entire habitat needed to reduce negative effects (low diversity) of genetic drift and maintain a healthy adaptive population.  Again Franklin's model is very dependent on species and habitat and what controls are in place (a space habitat, I would imagine, would have a lot).

I'd have to think a bit on how well the 500 popsicles scenario, with AI injections (each generation, most likely) would work out.  I guess it could play out like, e.g. small bands of humans (50 per) in a forest which occasionally  meet up for wooing and intermarrying between the bands.  

 

Edited May 11 by TheVat
tupo

[Mgellis]

This is very helpful.  Thank you.