Reptile & Amphibian Forums

Could someone please explain the logic of % in hybrids,I need to pass this info to someone else but can't get my head round it.
If I breed a ruthens king to a greyband = babys 50% of each.
If I breed one of the 50% animals to a 100% greyband, what would be the result of the babys in % and why ? could someone explain how the sums work ? I've heard some say the babys will be 75% and others say 62.5%

So far this is the third or fourth post in like 3 days I've read on this. I could just post a link to the other answers, but I'm really really bored, so here goes:

Ruthvens DNA: RRRRRRRR
Alterna DNA: aaaaaaaa

The F1's would all have the same DNA as each parent passes on 1/2 of theirs.

F1's DNA: RaRaRaRa

Those now also pass on q/2 their DNA. That could be any of the following as it is random.

Poss sperm/egg: RRRR, RRRa, RRaa, Raaa, aaaa

Crossing this back to a pure Alterna you would get these results:

aaaaaaaa X RaRaRaRa =

aaaaRRRR 50/50 (same as RaRaRaRa)
aaaaRRRa 62.5/37.5
aaaaRRaa 75/25
aaaaRaaa 12.5/87.5
aaaaaaaa 100%

Therefore the babies would be anywhere from 50/50 to 100% Alterna, and BOTH sources you got your info from (75% Alterna, or 62.5% Alterna) are correct, yet wrong at the same time. This is because it is possible to get either percentage in any one baby, but you will never know how much of either is actually in any of them.

Also note that there are MANY more codons than just 8 in snakes, so these numbers are just representatives of the possible outcomes.

Joseph

"Crossing this(Ruthven's x alterna) back to a pure Alterna you (could) get these results:
aaaaaaaa = pure alterna"

Or assuming 36 chromosones as typical for colubrids what are the odds of Ra(x36) aa(x36) = aa(x36)?

And when disscussing such F1 parental backcrosses in general shouldn't the simple 75%/25% be used unless you are discussing specific amimals that have been tested as to exact genetics?

There is NO PERCENTAGE! Once you create a hybrid it no longer belongs to either of the parental groups. It is it's own animal and not a % of another. If you cross a Ruthvens with an Alterna, you have a hybrid that you can name whatever you want, but no matter HOW many times you breed it back to an alterna, it will NEVER be an alterna again. It doesn't matter if its 3 generations or 5000 generations, it's STILL A HYBRID. And no matter how many times it's been "back bred" it should always be advertised as such.

Someone should talk to Jeff about creating a catagory in the classifieds just for hybrids. I personally hate seeing the "Albino Gray Banded Kingsnake" offers in the Gray Band section. They are not Albino alterna, and never will be.

Just my opinion, but who knows, I could be full of it.

I agree with most of what you have said, once a hybrid always a hybrid.But, using the greyband again, if you keep breeding greyband back in, the animal will be more greyband than ruthens = a higher % of greyband.

It will never be a higher percentage of grayband. There is no grayband left! It is what it is. It's a hybrid.

If you bred a Bonobo with a human, and then crossed that offspring back to a human would the produced offspring be anything else than a hybrid?

I'm talking about genes here, yes it will always be a hybrid, but if you breed more greyband in, the result will be that the young will have more greyband gene than ruthens.Makes sence to me.
I was hoping for others to have something to say. ?

Genetically the resulting offspring will phenotypically resemble a gray banded king more closely if you kept reverting back to gray bands. But it will still be a hybrid no matter what and the percentages are bogus!

Just remember to advertise accurately! "Hybrid Lampropeltis albinos that look something like what an albino gray band would look like if one actually did exist."

Genetically the resulting offspring will phenotypically resemble a gray banded king more closely if you kept reverting back to gray bands

I agree, thats due to the higher percentage of greyband genes.

But it will still be a hybrid no matter what and the percentages are bogus!

Again I have to agree, while the greyband gene would be higher, it would not be possible to give any accurate figure,as each hatchling would have different levels/amounts of genes from type of snake.To me it can only be a rough guide.

I view 50/ruthveni x 50/alterna as crosses but over 50/50 view as gray bandeds.when you cross the damage is done cos if you was lucky enough to fine a pure albino how are you going to convince the world it's pure.Do you have the contacts can you get the people to part with there hard earn'd cash on your say so.

75% albino gray banded around $250

pure albino gray banded may be around $1000

Would you ???

Gazz
I don't disagree with you at all, what I'm trying to do is find the logic that says when breeding a greyband back in, some breeders will call them 62.5 % others will use 75% , I'm interested in the maths only.The logic of how they work it out.Opinons on hybrids differ, I understand that, I beleave there's room in the hobby for hybrids and when you say the damage is done, I would put it like that.

100%ruthveni X 100%alterna = 50%ruthveni/50%alterna

50%ruthveni/50%alterna X 100%alterna = 75%alterna/25%ruthveni.

50%ruthveni/50%alterna X 75%alterna/25%ruthveni = 62.5%alterna/
37.5%ruthveni.

75%alterna/25%ruthveni X 100%alterna = 87.5%alterna/ 37.5%ruthveni.And so on.