Reptile & Amphibian Forums

The subject of outcrossing came up in a discussion I was having today. IE: when working with color morphs etc that are simple recessive genes how often do you guys think it is required to keep a line strong.

The second question on locale specific animals how big a group do you need to prevent the inherent problems of too close breeding for truely non related animals in your opinion.

Thrid what constitutes a locale specific animal, 10,30,50 or 100 mile radius

I will go ahead and state my practices for the record so as not to blind side anyone.

If we are going to work with a locale group we try and maintain 3-4 males with 5 female as a small group.

and on the color morphs we try and go back out for new blood every 4th to 5th generation.

As far as locales we consider them differently, for instance the 277 hwy bulls conme from exactly that anywhere along the 277 highway, Miami County bulls come from only Miami County Kansas, Kankakee prarie animals only from there, South Texas bulls from Laredo down to the tip of Texas and back up to Refugio etc. etc.

Just interested in everyone's opinion.

May everyone have a happy and properous new year,

John Cherry
Cherryville Farms

Good thoughts.

I've never read any studies made about population genetics and inbreeding with pituophis. However, there was a study done with a locale of european adders, Vipera berus, in which gene flow was absent and the population was declining supposedly to inbreeding. New animals were ultimately introduced to bolster the gene pool, but I'm not sure of any ongoing studies taking place.

Outcrossing is good for captive populations, and I wish more people would do it, lest we may get more "bug eye" traits like those seen in leucistic texas rat snakes. Unfortunately, breeders want more of a certain morph produced, and genetic integrity may be sacrificed for the almighty dollar.

Neil

one note about inbreeding; many studies of wild animal populations, from monkeys to mice, have shown that it only takes a very low level of gene flow - i.e. outcrossing - to prevent any negative effects of inbreeding. In the wild, one immigrant animal every several generations can be enough. Captive breeders don't need to worry too much about it, unless it goes on for a number of generations - or unless a harmful trait pops up at some point.

Craig

I understand what you are saying about the dollar issue, but I really believe it is not as big an issue as it was several years back when prices of colubrids were so high. Now with the folks I am talking to, diversity and genetic make up is more of an issue as the long term viability of a strain seems to be MOST breeders top concern. To me this is a real good thing and I hope the trend continues. It seems that most of the get rich at any cost have moved into some of the more profitable animals such as Ball Pythons etc. It will be interesting to watch that market over the next few years to see what happens to the pricing and the players involved. Personally I can't wait for the prices of the albino ball to get down to a really affordable level as I think they are beautiful. By the way the study you mentined on the vipera had a follow up and due to the follow with telementry and release of a few new animals it seems some of the problems are correcting themselves. The researchers are catching flack for the release of potencially "dangerous" aniamls though and the study is woefully underfunded.

John Cherry
Cherryville Farms

Great series of questions John. This would be my take,

1) I don't work with any color morphs, but if I did I would use the same rule of thumb you proposed.

2) This is a tough one. The larger the group the better but there will be times when obtaining a sizeable group is very difficult. A case in point would be the Ky locality pine snakes we work with. It may never be possible to ever put together a group as large as we would like so there will almost certainly be some inbreeding going on at some point. A trade off we will have to make in order to maintain pure lines. We hope that as our project progresses this will be kept to a minimum and new genetic material from the same locale comes our way. In the mean time we will work with the small group we have. Our first breeding should be totally unrelated snakes though using a captive produced male and a female we field collected in 2003.

Here's a pic of our male pine snake. We also have some of his siblings (all female) that we hope to find an unrelated male to breed with. These snakes are really hard to come by but maybe lady luck will smile down upon us and bring us another male. We spend a great deal of time and effort on this so hopefully this will be rewarded.

3) We consider the same population to be locale specific. The closer the better but of course this is not always easy. Two snakes from the same site or within a few miles would be ideal. County is a nice criteria and is a good one to go with as well. County lines mean nothing to the snakes but for us herpers it gives us a frame work as to population. The most meaningful to me is whether the snakes are the same population. For example, the pine snakes we work with occur only in portions of three counties in western Ky. This is a relatively small area and I would consider all of these snakes to be of the same population. From the same county would be even better, but this is a workable situation for us. The pine snakes that we keep are one of those locality situations where due to the snakes scarcity some compromises may have to be made. Two snakes from the same population but different counties being bred together and the potential for some inbreeding to occur down the road though we hope not.

A much easier locality project would be the one we have with Ky locality corn snakes. These snakes are an isolate with a very restricted range but are common enough where we can easily bring new blood in at any time.

Well, I guess thats my take on it. Thanks for posting this discussion topic. Phil

Good question John.

I would think that locale specific label would vary with the species, their size, their home range, and their habitat preference. For instance, I'd assume that(western)pits and racers have a large home range, so a locality specific area for them would be much larger than a locality specific area for a niche species like a scarlet king.

County info is good for species in some parts of the US, but can be almost meaningless in areas in TX (Brewster Co) or CA (Riverside).

Road locality info is good when the road is relatively short, but what if it extends 10, 20 or 30 miles?

Paul B