Help With Managing Limited Gene Pools

P

Pouchie

Member
Can anybody help me? I am looking for someone who might be able to help me with information on how to manage small populations of animals that are to be bred for genetic diversity.

Does anybody know any good resources that might help me?

Anybody involved in breeding programmes where there are a limited number of individuals?


I am interested in things like methods of maintaining diversity, minimum number of foundation pairs, best way forward when some founder pairs fail to breed, acceptable inbreeding coefficients, when a population becomes too limited to be a useful insurance population for the wild and basics like do you always have to look for new blood or can a population be self sustaining?

I am also interested in anything anybody knows about the wild.. how unrelated ARE wild animals? Surely every mating that happens can't be completely unrelated and surely there must be some relatedness between animals in a given area.

Sorry to be so boring, I know its not the most exciting subject in the world but I'd be eternally grateful for any help because I am trying to manage some rare rodent populations (rare in captivity, not endangered).
 
I disagree - to me it is not a boring subject at all and I think it could start an interesting thread here on this quite special forum.
 
Any good conservation biology primer will do with a part on population management is useful. The principles of any captive programme where populations are concerned is the same whether small or large. For the principle it is all the same.

1) Get yourself a copy of Wild Mammals in Captivity Eds. Devra Kleiman et al
2) Check out the captive programme for riverine rabbit (Bunolagus monticularis) in South Africa.

PM me if you will.

Out of interest: what species of rodent are you managing?
(jirds, mice ...?)
 
Thankyou very much for the response. I am working on Tristrams Jirds Meriones tristrami originating from Plzen and also want to make sure one of my other projects (Cricetomys emini) is on the right track.
 
Pouchie said:
I am also interested in anything anybody knows about the wild.. how unrelated ARE wild animals? Surely every mating that happens can't be completely unrelated and surely there must be some relatedness between animals in a given area.
Click to expand...

A very interesting question and one that is often overlooked when discussing management of Zoo populations, where breeding related animals together is often regarded as taboo. This is probably because there seems to be an aim of managed populations of zoo species to maintain '90% genetic diversity in 100 years' and any inbreeding would obviously work against that.

In larger unmanaged populations in the wild there must be inbreeding, despite the behaviours such as emigration out of herds & groups etc that work to control it. I am quite sure that Gorilla groups(and probably other Apes and monkeys too) in the wild contain many related animals and that there is some inbreeding at work too. In the Wild the individual Gorillas in troops all closely resemble each other- indicating long term familial relatedness leading to similar appearance, such as you might find in primitive human families or tribes- you don't see this very much in captive groups where animals from different sources are brought together and never (deliberately) allowed to inbreed.

Also consider species like the Cheetah and Pere David Deer, Golden Hamster etc where the existing populations must be very inbred as they are derived from very small founder-bases after population bottlenecks, either natural or manmade, have occurred.
 
Pertinax said:
Also consider species like the Cheetah and Pere David Deer, Golden Hamster etc where the existing populations must be very inbred as they are derived from very small founder-bases after population bottlenecks, either natural or manmade, have occurred.
Click to expand...

Or what to think of Island populations where most of the species especially on remote island are coming from a very small founder stock.
 
So is the answer to continue breeding with the gene pools you've got but try to use each set of genes as little as possible? Then if a health problem arises stop that line?

I presume the zoo breeding programmes must have some sort of model to work to.

For example in one of our breeding programmes we had 4 pairs to start with but 2 pairs failed to breed. Would the next step then be to outcross the successfully bred offspring to the unrelated animals that failed as founders?

Then what? The gene pool will obviously get small quite fast if no further unrelated individuals can be obtained.

That is really what I am looking for. A method of keeping the gene pool as wide as possible for as long as possible but it seems to get a little complicated when certain pairs fail to breed together but will breed with different mates.

Im just wondering how useful these animals would then be conservation wise. I suppose once they become genetically different from wild samples and begin to domesticate, they become useless.
 
Pouchie said:
So is the answer to continue breeding with the gene pools you've got but try to use each set of genes as little as possible? Then if a health problem arises stop that line?

I presume the zoo breeding programmes must have some sort of model to work to.

For example in one of our breeding programmes we had 4 pairs to start with but 2 pairs failed to breed. Would the next step then be to outcross the successfully bred offspring to the unrelated animals that failed as founders?

Then what? The gene pool will obviously get small quite fast if no further unrelated individuals can be obtained.

That is really what I am looking for. A method of keeping the gene pool as wide as possible for as long as possible but it seems to get a little complicated when certain pairs fail to breed together but will breed with different mates.

Im just wondering how useful these animals would then be conservation wise. I suppose once they become genetically different from wild samples and begin to domesticate, they become useless.
Click to expand...

The issue is relevant in any zoo breeding programme. I would concur that breeding your F1's to the failed first generation founders (4 individuals) is a worthy strategy.

I will try and send on some material on the CBSG and all. Their VORTEX programme shows what stochastic events may do in the long term.

I agree with other posters that most species - even us Homo sapiens - have gone through a genetic bottleneck at some point in our evolution. It is true for almost all species alive today.

What is normally important in genetics is to spread around the genes as wide as possible in as many combinations in order to achieve a maximum genetic diversity in the entire population.

However, most of the mammalian genetic studies - allthough not the H. sapiens one - have been based around quite small portions of the entire species range and habitat type. F.i. the famous cheetah research has concentrated on Southern African cheetah genetics and not any other populations in East African, North or West Africa (or even the Asiatic one ... allthough the Indians would have us believe there is simply no difference ... there is a lack of scientifically verified data on this ... to put it plainly ... it has never been done yet).

When the genetics of North-East African cheetah from Sudan, Ethiopia and Somalia were studied, it was found these were quite different - and in effect not surprisingly so given the entirely different biome, habitat and zoogeographic region of the taxon - from the South African ones. This has now quite rightly led EEP managers to separate both populations into 2 ESU units.
 
I really would be grateful if you could send the info you mentioned on to me. I think I need to put more work into planning the maximum combination of genes aswell as that is something I haven't needed to put much thought into yet. Thanks for mentioning this.

Going back to something you recommended I look at earlier, the Riverine Rabbit - is there actually a captive breeding programme? The only info I could find was that there were circa 250 adults left and that they only produce 1-2 kits per year which meant that the conservationists decided not to risk taking any for a CB project until they learned more about the species and were sure they could make a success of it. Just wondered if this report was old and they have now in fact embarked on a captive breeding programme?
 
You must log in or register to reply here.
Back
Top