This pick should help a little it shows the crosses and the offspring they should produce once the traits are dominate
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| Breeding fish for specific traits http://byap.backyardmagazines.com/forum/viewtopic.php?f=2&t=934 |
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| Author: | Caribean-grower [ Dec 15th, '06, 21:13 ] | ||
| Post subject: | Breeding fish for specific traits | ||
This pick should help a little it shows the crosses and the offspring they should produce once the traits are dominate
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| Author: | janethesselberth [ Dec 16th, '06, 00:39 ] |
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Exactly CG! (Gawds, he's got Punnett Squares and everything!!) So if you wanted to lock in pink, 25% of your F2 can be used. If you wanted big and pink, then 3/16 could be used. Your second generation (F1) looks all gray because the gray is dominant over pink. I actually was starting to verbally describe just using pink and gray, but decided not to bore everyone. Your picture is much nicer, and I like the demonstration with the size factor, too. All of this assumes that the colors are either/or, and do not blend. If F1 turns out mauve instead of gray, then you just have to keep selecting for colors closer to what you want. Goodness knows how long that will take. Regrettably, I think fish color is probably blendy. |
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| Author: | Caribean-grower [ Dec 16th, '06, 04:11 ] |
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I was hoping you would like it Janet. As you could see i like Mendel as well Yup i think fish colour tents to blend too, but as she said pick closer to what you want you could put size shape what ever trait you want in the place of the colour(Bb) or size (Ss). And a easier way to "lock in" traits would be the back-cross which would be the younger generation to the older gen. eg. granddad to granddaughter. This is done to lock or fix a trait so it "breeds true". However in breeding is not desirable because it weakens the fish line but is a useful tool to the skilled breeder. I myself like to back-cross the F2 gen to the F1 gen simply because the F1 gen has ALL THE GENES whither dominant or recessive but that's for a next time ( or someone elese(Janet) to describe ) |
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| Author: | Daniel [ Dec 16th, '06, 05:20 ] |
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If you get two people working on the same traits, every couple of generations you could outcross, to keep the traits but increase genetic diversity |
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| Author: | aquamad [ Dec 18th, '06, 21:04 ] |
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I remember this stuff from year 11 and year 12 biology lessons - it can get confusing , but I love it all the same - had a friend who tried it with guppies so as to get females with more colour - he had some sucess... |
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| Author: | TimC [ Dec 19th, '06, 09:33 ] |
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It works in theory, just depends on the trait and other factors. When the theory says 50/50 usually you will only get one or the other, unless it is a perfectly controlled environment... I was breeding swordtails a few years a go and tried mixing colours, I had an orange male and white and gold females. The only babies I ever got from either females was the same orange colour as the male. The books and info I had said I should get some variation. My biol. teacher said sometimes, specific genes can be more 'potent' than others, or to some extent more dominant. It takes particulat triggers to obtain specific variation results. |
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| Author: | Caribean-grower [ Dec 19th, '06, 23:55 ] |
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Ah Timc take a look at the pic and you will see in the f1 generation that all the fish look the same way, these are the hybrid's. Hybrid means a cross of two different types off fish. These fish (The F1 in the pic) contain all the genes off both the parents (P1) but only the most dominant / potent ones will show but the lesser ones are in there as well this is why a hybrid grows faster / better than 'normal' and is referred to as hybrid vigor. Upon crossing the F1 gen (the baby sword-tail) then you should have gotten some variation |
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| Author: | TimC [ Dec 20th, '06, 20:10 ] |
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I always hated genetics... 
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| Author: | johnnie7au [ Dec 20th, '06, 20:25 ] |
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.. I guess we must be a little careful here ... when we talk about type ... species ... subspecies etc. etc. What I wish to do .. is look for a mutation within a family .. and fix it! Then look for a similar mutation within an unrelated family (but same species and subspecies family .. ie. mossambiques ... not hybrids ...) so I can get a "Pure strain" of a particular characteristic ... in other words ... I don't wish to get into nile / moissambique crosses .. etc. etc... Rather a pure ... mutant strain of 100 % mossambiques .. with whatever mutant characteristic develops first. I may be dreaming .. sounds difficult to me ... |
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| Author: | janethesselberth [ Dec 20th, '06, 21:37 ] |
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Johnny, What you are talking about is perfectly feasible, and is really what we are talking about. People are using the word 'hybrid' a bit too liberally. If we assume that 'pink' is the mutation in CG's picture, it all follows. The problem is that it may take many generations to fix a trait if the trait does not express cleanly. For example, if breeding pink and gray fish gives mauve, it's going to take a lot longer to fix on pink. The other complication for you is that your 'pure' mozambique is probably already a hybrid because that seems to be what is available in the industry. |
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