yg cacs genetics question

[scott]

my female yg recently spawned with a triple red. the fry are still very small. my question is will all the fry be standard color form or will some be yg? i can't tell yet as they are still to young. a lfs wants yg's and is willing to pay a decent price. the problem is i only have 2 females. well i do have a male but i believe he is sterile.

 

[Tea]

fry

Hello there Scott you will end up with a good mix of fry. Imo I have had triple red male spawn with yg female I got a mix of color, some were yg others were triple red. Yg cacatuoides usually have more genetic problems as they are breed specifically for color. hope this helps.

 

[scott]

thanks, i thought that maybe you needed both yg parents to get yg offspring. i wish i paid more attention in biology class back in school. i am aware of the problems with yg's. stores in my area are willing to pay alot more for yg's than standard tr, dr, and of variants. i don't breed them as a source of income or anything but getting store credits really offsets the costs associated with the hobby.

 

[fishgeek]

if and i dont know for sure
your yg gene is recessive then anything that shows that colour will produce all sex cells with that colour trait

this means that in your cross between the red and yg, it is the tr that has sway , assuming simple dominance recessive gentics at best you could hope for 50% yg and this will only be true if the tr is a heterozygous individual, ie it is showing characteristics determined by the dominat gene and carrying a recessive gene
if your tr is homozygous and inheritence is simple you will get no yg fish at all

thats about all school would have helped with

as far as genetics for these guys go , there is an article on the main site, though i dont believe we know whether it's simple/co-dominance
multiple alleles etc
maybe others have more experience with the genetics you are interested in

 

[kribs]

I did a cross with a YG times a OF female. All the babies were OF. Then I also did a cross with a TR female times a YG male. the babies were all TR. The white will not show in the F1s it will show in the F2 generation u have to take the F1 offspring and cross it back to the YG to get YG cacs. Also if the TR that you have is carrying the YG gene then you will get a 50/50 ratio.

 

[dm01]

kribs, I am curious if you ever tried to cross true-breeding (homozygous) TR with OF to see which one is dominant (sorry I am a genetics buff)

 

[_BaDgUy_]

I'd have to go with kribs observations...

Since the yg gene is recessive, it needs the same gene in the other sexe to show up.

Example :

YG Male with a TR female. Only the YG male has the recessive gene.
None of the offsprings will have the recessive YG color, but all will have the YG recessive gene.

If afterwards wou mate 2 of those offsprings with the recessive gene, you will have some YG show up, but I don't remember by which ratio

If you mate one off the female offsprings with the YG male, once again, you will have YG show up, but once again, I don't remember the ratio.

I could be wrong on this. I've read a bit on betta genetics in the past, but nothing too much in depth. I'll try to read a bit more on the subject.

 

[dm01]

So, this all seems to be a basic mendelian genetics with multiple alleles and simple dominance:

YG is a recessive allele. Cross of two YG individuals always gives a YG progeny ("true-breeding").

TR and OF are dominant alleles in respect to YG, and one of them is also dominant to the other, however, one needs to see a TR x OF cross to say which one.

A TR or OF fish can be homozygous (true-breeding) or heterozygous (having one TR or OF allele, and one YG allele).

A cross of a homozygous TR or OF with a YG gives all babies TR or OF, respectively (as the kribs has observed)

However, if you cross a heterozygous TR fish to a YG, you see both TR and YG progeny (50/50, again as the kribs has correctly mentioned earlier).

When you cross two heterozygous TR's, you will see 75% TR and 25% YR. Within these 75%, 25% will represent true-breeding (homozygous) TR and 50% will represent heterozygous TR (having a YG allele).

It would be interesting to see more postings with results of such crosses, to see if this theory is correct or not.

 

[depthc]

Great lesson on genetics dm01. You couldnt of summed it all up better.

 

[scott]

give me some time and i'll keep you posted on my progress. i have to assume that my tr is probably homozygous so i will probably have to cross one of the male ofspring with the yg female to get any yg's. the fry i have now are still small but they all seem to have some color but its to early to tell for sure. after reading dm01's post my biology lessons came flooding back to me. if i remember correctly a punnet square is the method of figuring out the ratio's. my goal is to get as many yg's as possible. this would have been much easier if my original yg male was not sterile. so i have to start with only 2 yg females and tr males. i understand how the tr and yg traits work with tr being dominant and yg being recessive but where does the of come in. i beleive if you cross 2 tr's you will always get tr offspring but if you cross 2 of's you will get a mix of tr and of. so is tr still dominant over of?

 

[dm01]

Scott, I am curious what you will get, so keep us posted; all theories mean nothing compared to facts.

You say "i beleive if you cross 2 tr's you will always get tr offspring but if you cross 2 of's you will get a mix of tr and of. so is tr still dominant over of?" Is it always so that a cross of two OF gives some TR? Are there any true-breeding OF? Maybe OF is lethal when homozygous (things like that do happen) and all OF are heterozygous?

In any case, if two OF's produce some TR offspring, then I'd say that OF is dominant to TR, because even if the fish looks OF it must have a TR allele.

 

[scott]

i beleive if you cross 2 tr's you will always get tr offspring but if you cross 2 of's you will get a mix of tr and of. so is tr still dominant over of?

i'm not 100% sure of this. all i know is from my own experiences. in the past i have crossed tr's and always got tr and dr offspring. a friend of mine had a male and female of and the offspring were a mix of tr, dr and of. so as you said the of could be dominant. is it possible for it to be dominant sometimes and not others. i'm not anexpert in this by a long shot but it seems to me if the of was dominant we would be seeing more of in the lfs'. although there are of's available there always seem to be many more tr's and dr's . that's just an observation on my part it may mean absolutely nothing.

 

[fishgeek]

i think the problem is that genetics is very rarely simple, other than for explanations in high school biology classe's

and phenotype's will not alays allow us to understand genotype

it may in these fish be a case of co-dominance
multiple allele's

i dont believe we actually know

andrew

 

[scott]

i somewhat understand all of this. the thing is tr is not really dominant over yg because the yg cac also shows the tr traits ie. red dorsal, caudal and anal fins. also a yg can show the of traits as well ie. orange dorsal caudal and anal fins. is this what is know as partial dominance or something else. all of this confusing genetics aside, i would like to eventually have fish producing offspring that show the yg/of traits because they will bring the most money at the lfs. i think that i might have to cross a wild cac into the mix occaisonally to keep the gene pool fresh. i'm not quite sure how to do this other than crossing a wild cac with a yg and then crossing the offspring back with the yg. unfortunately i will probably have to do alot of culling along the way because these yg's always seem to have alot of problems such as bent spines and swim bladder deformities not tho mention the infertile male i already have in my discus "show tank". although the cacatuoides is probably the most commonly seen apistogramma it is the most interesting to breed, in my opinion at least.

 

[fishgeek]

line or inbreeding in any species is used to fix a trait , outcrossing with new blood is used to try and diversify and the gene pol and hopefully reduce the changes of birth defects from becoming fixed with the desired trait

andrew

 

[dm01]

i think the problem is that genetics is very rarely simple, other than for explanations in high school biology classe's and phenotype's will not alays allow us to understand genotype

it may in these fish be a case of co-dominance
multiple allele's

i dont believe we actually know

andrew

I think I have to agree that this can be more complicated than what the few examples that we had discussed earlier tell us. In any case, the approach that Scott wants to take (cross his YG with w/t and backcross the F1 to the parental YG) is what I would do.