Make Sense Of My Genetics Ramblings...

[OohFeeshy]

I got incredibly bored when we were supposed to be revising today, so I had a quick look through the genetics section in the Biology book and got inspired. So followed a long time of punnets squares and frantic scribbling.

I was trying to work out how to start and albino line.

Lets say A is the dominant non-albino trait and a is the ressecive albino trait.

To get 100% aa by f3, the easiest way would probably be with one AA parent and one Aa parent for f1. Question- As a rough guide I used the human chance of being Aa, which is 1/70, but what do you reckon it is for bettas? Apparently cambodians are semi albino, but whether that means they're Aa or not, I don't know. And if you leave it down to luck, would it be more likely a white opaque betta is Aa than, say, a steel blue one?

For the AA parent, I thought using a dark colour like melano or steel blue might be best, in theory so the ones that are more 'albino' show up better.

So if you have a Aa parent and an AA parent, 50% of the spawn should be Aa.

For the f2, either two Aa (again, if not obvious, guesswork is needed) or one Aa and, if possible, the original Aa parent. This spawn should produce 25% aa. Bingo.

Then the f3, two aa's, should make 100% albinos.

This all sounds slightly too straightforward to me, so can any other people who are sad like me verify I'm slightly right?


I also did some 'how to get ctdtpk's from scratch, then added in my albino line, making some rogh guesses as to how many spawns it would take to get 100% CTDTPK albinos... About 10 spawns, I made it.


EDIT- OK, so getting any albinos is unlikely, apparently...

Albinism in animals, for example, affects more than pigmentation. In many cases vision is impaired and growth rate is reduced relative to the normally pigmented siblings. When an albino Betta (Siamese Fighting Fish) was mated with a normal female, and the offspring were mated, Mendelian calculations would lead us to expect that about 1 of 4 would be albino. In fact there were none.

A larger progeny would not improve the survival rate of the albinos. Bettas spawn for 4 to 5 hours, and the eggs hatch over a similar period. The first fry to hatch begin feeding sooner, and grow so fast that they can eat their younger siblings.

The albinos develop more slowly, and are thus smaller than siblings of the same age. When they hatch, their poor eyesight limits their ability to feed and grow. It is no surprise that the albinos were selectively eliminated from the progeny. Fish food!

Just as a random response to that, what effects would jarring the fry as soon as they appear have?

 

[Squid]

This all sounds slightly too straightforward to me

Funny.. thats not what my brain was telling me..

Good luck with that one..


Squid

 

[OohFeeshy]

LOL, thats just my writing. Pretty much, three spawns- first, one to get all non-albinos, but carrying the albino gene, the next to get a few albinos and the last to get all albinos.
Another thought, assuming the albino fry would have no colour (ie, not be the traditional 'black eyelashes' fry are), wouldn't you be able to spot the albino fry fairly early? Thus being able to seperate them early on?

 

[Ginge]

Yeah i do see where you are going there i take and i does make sense.

 

[Synirr]

Yep, that's basically how it works, but since albino fry are so fragile it's difficult (but not impossible) to actually raise them to adulthood. I've heard rumors that they're often sterile too, but there is one confirmed case of an albino betta producing a spawn, though I can't remember the breeder at the moment... I think the albino fish was female. Apparently no successful albino lines were produced using those heterozygous fish, but I personally don't think it's an impossible goal, just a very difficult one, especially considering the lack of material we've got to work with

Strictly speaking, albinism is defined as the absense of pigment, so while cambodians are semi-albino in this sense (lacking pigment on their bodies), they're not albino in the way we're looking for, which is full body albinism. No colour is any more likely to carry that gene than any other, I wouldn't think, and if they are it's by pure chance, so a white fish isn't more likely to produce albinos. There are many different types of albinism, and in some a minimal amount of pigment actually is present in the cells. In bettas, I imagine these are the fish we see surviving to adulthood, and the ones we'd want to breed, as they would have basically the same look but fewer health problems than those with no pigment. There are also fish with ocular albinism, albinism restricted to the eyes only... I've seen a couple of (what I suspect to be) these floating around, but they might have also been xanthic or something, as I've only seen them in red/white combos.

If you were to start an albino line chances are you'd want to start with a aa homozygous albino fish and a AA homozygous normal fish, simply because your chances of finding a confirmed Aa fish are... well, like I said, there's only one confirmed case of an albino producing offspring that I know of. Those would be the only sure-fire Aa fish under the sun unless you were lucky enough to find a pair that consistently produced a small number of albino offspring in their spawns.

Yes, you *should*, in theory, be able to tell from the moment of hatching if a fry is albino based on the red eyes. You can, after all, spot the cambodians in a cambo spawn . Little white tummies. I also think that you could raise a pretty good number of albinos to adulthood given special care; they shouldn't be housed with more robust siblings, obviously. That would be the hardest task, then once you have a handful of breeding stock to choose from it becomes a matter of linebreeding for healthy fish.

I dunno if you know this trick, but to avoid complex punnett squares in the future, if you wanna figure out % outcomes of crosses you just multiply the chances of getting each allele you're looking for from each parent to get your answer... say you're crossing a Aa fish to another Aa fish and you want to know what the likelihood of getting a aa fish would be, you multiply 50% (chance of getting a from the first parent) times 50% (chance of getting a from the second parent) to get 25%, or 1 in 4 offspring . You can do this for any type of cross, dihybrid, trihybrid, etc.

 

[Synirr]

Coincidentally, I just got an email in response to my want ad for betta oddities on Aquabid.... this guys says he has an albino CT for me! He's gonna send a pic, so we'll see. Hopefully it's real and affordable, hehe . First real response I've gotten to that thing, wow

 

[OohFeeshy]

Thanks for that Synirr The only reason I said use a hetrozygous albino was that I thought it would be slightly easier to find than a homozygous albino, although after reading your post I remembered that I'd seen a few albinos advertised around... But as you said, whether they actually can breed or not is uncertain(possibly similar to the melano trait). Lucky you on the offer of an albino CT though! Even if you can't afford it, I know I'd be willing to loose a few internal organs to the black market . Thanks for the tip on the Punnets, but I have too much time to bother with the easy method Hey, I spent my revision time this morning doing all the questions in the genetics section... I'm embarrased to say I found them ridiculously easy . But for now, I think I'll continue some searches into the bowels of google, theres some pretty good info behind all the adverts for scam websites...

 

[Synirr]

No reply yet about the albino, but it's probably not time to wake up yet in whatever country to seller is from . I got his email around 4AM. It asked "do you interested?"

 

[OohFeeshy]

LOL, yes, you do very interested indeed