Reduced Hets

[riverboy]

I am having a hard time finding out reduced percentages of hets. For example
a 50% het for something further reduced by breeding with a normal. Anybody know this stuff?:main_huh:

 

[fallen_angel]

Hmmm, well if one 100% het. gecko and one "non-het" gecko breed, they make the 50% hets.. so I would think that a 50% het. gecko and a non-het gecko would make 25% hets.. that's just an educated guess, I could be totally wrong

 

[nwheat]

With recessive traits, the normals and hets look the same. You could statistically get both normals and hets in your clutch and there is no way to pick out the hets - so we use a probability.

The percentage refers to the probability that the animal actually is a het.

So, using albino as an example, an animal that is 100% het albino is definitely a het and will produce half albinos and half normals if bred to an albino.

An animal that is 50% het may or may not actually carry the recessive allele at all. It means there is a 50% chance that the animal ended up with the recessive allele and a 50% chance that it is just a normal and does not carry the allele.

Aa x AA (het albino x normal)
Offspring will be: 1/2 AA (normal) and 1/2 Aa (het) but they will all look alike. Statistically we would expect half to be hets, so we call all of the off spring 50% possible het albino.

Aa x Aa (het x het)
Offspring will be: 1/4 AA (normal), 1/2 Aa (het) and 1/4 aa (albino). Out of 4 offspring we expect one to be an albino - the other three will be either normals or hets, we don't know which is which. Two of the remaining three are expected to be hets, so we say that they are 66% possible hets.

Hope this helps! I have some genetics info on my site that may also help.

Edit: I may have misunderstood the original question.
I really don't like the practice of assigning percentages when breeding unproven possible hets. Either they were het or they weren't and assigning these low percentages really just confuses things. I do think it is important to note that offspring are possibly het for a trait, but I don't think it is necessary to go with something like "this animal is 12.5% possible het" when it really could be more like 66% if both parents are actually hets.

 

[fallen_angel]

I agree and forgot about that detail, that the 50% het would actually have to be a true het for anything to really matter, so you would have to prove the het. out through breeding

 

[MSMD]

I really don't like the practice of assigning percentages when breeding unproven possible hets. Either they were het or they weren't and assigning these low percentages really just confuses things. I do think it is important to note that offspring are possibly het for a trait, but I don't think it is necessary to go with something like "this animal is 12.5% possible het" when it really could be more like 66% if both parents are actually hets.

I totally agree. If you are dealing with parents that are for sure 100% hets, then the 50%, 66%, etc. hets can be labeled with accuracy. However, when unsure of the actual genetic inheritence of the parents, I think it's just important to make sure that it is known that there is a possibility of being het for a certain trait, with the probability being unknown. JMHO

 

[shadowx362]

sorry but how can you know to label something 66% instead of 50%?

 

[fallen_angel]

Aa = het. or heterozygous form, which means the trait is carried but not expressed

Aa X Aa (two hets.) =
AA, Aa, Aa, and aa

AA= homozygous, normal, no trait
Aa = het.
aa = recessive trait is expressed

meaning that out of 4 babies from two hets. 1 won't be a het, 2 will be a het, and 1 will express the trait (i.e. albino) and will be albino. 4-1 albino= 3 possible hets... but only 2 should really BE het, and 2 divided by 3 (posible hets) is 2/3 = 66.6%

 

[Nigel4less]

Het x Het equals 66% Het, Homo x Het= 100% Het, Het x Normal= 50% Het