Reptile & Amphibian Forums

If you breed two 100% Hets the resulting morphs are out of the equation and the rest look normal but may or may not be Hets. Are these 50% Het or 66% Het and what exactly is the other one? Or are these two names for the same thing?

Thanks for clearing this up.J
Bruce

66% hets are the normals when both parents are heterozygous for a recessive mutation and 50% hets are when only one parent was heterozygous. Your odds of getting a het really are better with the 66% chance ones so they are usually a little more expensive.

All you have to do is use a punnett square. You can go to pete kahls site for info on those, but here is the answer to your question. If you breed 2 hets together (assuming it is a simple recessive gene), use a punnet square to figure out what the babies will be.

B b
B BB Bb

b Bb bb

BB=normal
Bb=het
bb=homozygous

If you breed a het to a het, ou will get 25% normals, 50% will be hets, and another 25% wil display the trait. Since only 75% show normal pattern, only 75% can be hets. You know that 1/3 are not hets, and 2/3 are. Therefore you label all of them as 66% possible hets.

It doesn't always work out like that. For instance, I've had many clutches of het hypo to hypo brooks kings that ended up with mixed results. Last clutch was 12 eggs......9 hypos and 3 normals. I had 2x het ghost pair produce 16 eggs. The desired results for a 2x clubrid breeding.....at least to get a good mix. Results were 7 hypos, 2 axanthics, 5 normals. In another 2x het ghost breeding, I got 11 eggs. This was worse......10 normals and 1 dead in the egg axanthic. The whole 66% poss. het theory is just that....a theoretical probability. With het x het you could get all albinos.....or none. It's like playing the lottery.......only the numbers usually hit more.

peace
Brandon Osborne

Not like the lottery at all. More like flipping a coin. 66% hets have a 2 in 3 chance of carrying the trait in question. 50% hets have only a 1 in 2. Do you get variability within small sample sizes? Of course. The whole concept behind statistics and probability is that on average, you will get the stated results. Flip a coin in the air. Do it once. Whatever you get, you have landed outside the average. Flip it 10 times and keep track. Flip it 100 times and keep track. Flip it 1000 times and keep track. The more often you flip it, the closer to half heads and half tails you will get. - The law of averages. If you want to get complicated, we can get into statistics, population sizes (n), double (and triple) hets, etc. The logistics get harder to keep track of, but the principle is still the same. Why do you think casinos exist? They may lose $1M in a progressive super duper multi state jackpot, but they still make a fortune in the long run, because it all averages out, and the system is programmed so the house makes a percentage.

Hope this didn't ramble too bad, and if you take the math far enough, even the lottery applies. It's just the mother of all factorials

Regards,

Neil

Good point about small sample sizes, a good illustration of this is the guy who posted recently with 10 Pastel Jungles in a 10 egg clutch. Far less than a 1% chance of this happening, but it can happen (unless his Pastel is actually a super pastel).