Reptile & Amphibian Forums

Hi everyone. I had a quick genetics/breeding question. Any help would be appreciated.

Okay, if you breed two 100% hets for amel together am I correct in assuming (using my very basic high school genetics from years ago) that 1/4 of the offspring would be amel, 1/4th would be normal, and 1/2 would be 100% het? If so how would you tell the offspring apart? I assume the amel would be easy to tell, but would the hets and the normal be distinguishable from each other?

Thanks for any help and if I am completely off please correct me LOL

Jon

Hi Jon;

Two 100% hets for Amelanistic give on average 25% (1/4) Amelanistic, 25% (1/4) normals, and 50% (1/2) hets.
2 out of 3 of the normal looking ones will be het for Amelanistic, so 2/3 is a 66% possibility of het for Amelanstic.
You won't be able to tell the difference between the normals and the hets, so you can do a test breeding of your "66% chance for hets" to an Amelanistic Gecko to prove them out. If a "66% chance for het" actually is a het then when breeding it to an Amelanistic 50% (1/2) of the offspring will be Amelanistic and 50% (1/2) will be het for Amelanistic. The 66% chance of het for Amelanistic has now become a definite or 100% het by proving it out. If a "66% chance of het" is bred to an Amelanistic and none of the offspring is Amelanistic (this may take a few clutches to be sure) then it did not prove out and it is now a normal one. All of the offspring of the normal will be 100% het for Amelanistic because it was bred to an Amelanistic.
So a way to tell the hets from the normals in the case of a het to het breeding is by test breeding the normal looking offspring to an Amelanistic Gecko. Another option is to breed the normal looking offspring back to the parent which is known to be 100% het for Amelanistic. If the "66% chance for het" offspring proves out then there will be 25% (1/4) Amelanistics. the "66% chance for het" Gecko is now a definite or 100% het.
If the "66% chance for het" does not prove out by breeding it back to the parent then all offspring will be normal looking and 50% (1/2) will be normals and 50% (1/2) will be hets, so all the normal looking ones will be "50% chance for het".
Hope this helps,

Rob Reiding.

Yes, thank you that really does help. I appreciate the time you took to write out such a detailed response. Have a great day!

You are very welcome and I'm glad I could be of help to you.
Those numbers are all "chances". I can't believe my own luck in breeding a het for Amelanistic and striped female to an Amelanistic Tangerine Striped male. Out of four hatchlings all four (100%) are Amelanistic although theoretically there is a 50% chance for Amelanistic from that breeding. Two of those four are also striped, so that is exactly 50%.

Rob Reiding.