thoughts on inbreeding

[axolotl nerd]

i am repulsed by the amount of people on this site who say inbreeding animals, especially axolotls, is acceptable in any way. i believe it to be disgusting and unnatural, an abomination of life itself. this is my personal opinion, but one i feel very strongly about. i understand there is some level of inbreeding in all axolotls as a whole (im under the impression this was done to introduce morphs), however, i absolutely abhor the thought of inbreeding within an immediate family (such as two siblings, a parent and an offspring, etc.) why make the problem worse? why add to the genetic defects and poor gene pool? why not add “fresh blood” from different colonies to your breeding group?
i wanted to open a thread for discussion about this, and hope to hear the thoughts of others.

if someone could explain a reason as to why my opinion is invalid or illogical, i consider myself to be a very open minded person about most things, and am willing to discuss and learn.

 

[JM29]

Hi,
I won't tell you your opinion is invalid or illogical. I'll only try to document a little more what you're saying. Your conviction should be respected. Since it won’t cause any damage to the animals it’s Ok for me, I won't discuss it.

Axolotl (Ambystoma mexicanum) is included in the A. tigrinum group (subgenus Heterotriton sensu Dubois & Raffaëlli, 2012). All the species of this group breed in the water. Several males and females can meet in a given pool / lake margin portion. The males will let their spermatophores on the pond flour and the females will take them.
Taking into account the particular breeding mode among Ambystomatidae, incidental breeding between siblings is probably not unnatural, especially among small local populations.
That being said, regular breeding between siblings is probably not the rule, while distant cousins may often breed together.

Inbreeding can be non-voluntary : the captive axolotl population was generated since the 1860th starting with only 6 parents. It was only more than one century later that "fresh blood was added from Xochimilco. Nowadays, it has become inconceivable to add fresh blood from the wild, but you're right : it is possible to collectively make better gene flow within the captive axolotls population if exchanges are made more frequently (exchange an axolotl against another axolotl can sound silly but it's the best way to maintain sustainable fragmented populations or metapopulation sensu Levins, 1969). Obtaining low kinship coefficients (below 5%) is possible by this way.

There is also voluntary inbreeding, you mentionned it, which aim is to maintain rare morphs. It can lead to success (a fixed line) or failure (severe fertility loss, genetic diseases... and finally loss of the line). If a genetic trait is monogenic, there are other ways to maintain them, by complex breeding plans involving many individuals. That's more complex with polygenic traits or complex combinations. Whatever the strategy, the result is high kinship coefficients (around 30% ; I calculated it for Betta splendens but it's the same).

That's all !
Sorry for the length. I made a conference on this theme a few years ago, with the help of 2 friends, in a french caudate symposium and this was a kind of summary of it.

As a side remark : “fresh blood” need quarantine for a lot of non-genetic reasons.

 

[axolotl nerd]

Hi,
I won't tell you your opinion is invalid or illogical. I'll only try to document a little more what you're saying. Your conviction should be respected. Since it won’t cause any damage to the animals it’s Ok for me, I won't discuss it.

Axolotl (Ambystoma mexicanum) is included in the A. tigrinum group (subgenus Heterotriton sensu Dubois & Raffaëlli, 2012). All the species of this group breed in the water. Several males and females can meet in a given pool / lake margin portion. The males will let their spermatophores on the pond flour and the females will take them.
Taking into account the particular breeding mode among Ambystomatidae, incidental breeding between siblings is probably not unnatural, especially among small local populations.
That being said, regular breeding between siblings is probably not the rule, while distant cousins may often breed together.

Inbreeding can be non-voluntary : the captive axolotl population was generated since the 1860th starting with only 6 parents. It was only more than one century later that "fresh blood was added from Xochimilco. Nowadays, it has become inconceivable to add fresh blood from the wild, but you're right : it is possible to collectively make better gene flow within the captive axolotls population if exchanges are made more frequently (exchange an axolotl against another axolotl can sound silly but it's the best way to maintain sustainable fragmented populations or metapopulation sensu Levins, 1969). Obtaining low kinship coefficients (below 5%) is possible by this way.

There is also voluntary inbreeding, you mentionned it, which aim is to maintain rare morphs. It can lead to success (a fixed line) or failure (severe fertility loss, genetic diseases... and finally loss of the line). If a genetic trait is monogenic, there are other ways to maintain them, by complex breeding plans involving many individuals. That's more complex with polygenic traits or complex combinations. Whatever the strategy, the result is high kinship coefficients (around 30% ; I calculated it for Betta splendens but it's the same).

That's all !
Sorry for the length. I made a conference on this theme a few years ago, with the help of 2 friends, in a french caudate symposium and this was a kind of summary of it.

As a side remark : “fresh blood” need quarantine for a lot of non-genetic reasons.

thanks for the response!
overall i agree with everything you’ve said, and it was an interesting read. i definitely intend to read up on//study this more