Why Traits Are Gained and Lost
By Bryan Chin (Pacific American Singers chapter)

First published in the American Singer Club newsletter, July 1997.

American Singer breeders are always looking for ways to improve the quality and variety of song and often breed for a unique trait or use unrelated Singers to cross in to add new traits. When this is done a certain trait is bred for but sometimes another valuable trait is lost. One common reason is due to how the traits are genetically linked to one another. Genes will always stay on the same chromosome, except on the rare occasion of crossover (the gene exchange location with its matching gene on the other chromosome) or a mutation occurs. To better understand what happens let's refer back to and example from my article on 'Basic Genetics' on how genes are located on chromosomes. This example illustrated 3 chromosome pairs. I have also added and modified traits that did not appear on my previous article. (Warning! This is not exactly how the genes are arranged in the American Singer this is for demonstration purposes only.)

[ 3 Chromosome Pairs ]

Gene 'A' is for open beak phrase (Co-Dominant w/a)
Gene 'a' is for closed beak phrase(Co-Dominant w/A)

Gene 'D' is for roller sounds (Co-Dominant w/d)
Gene 'd' is for flute sounds (Co-Dominant w/D)

Gene 'E' is for Self colored bird (Co-dominant w/e)
Gene 'e' is for Clear colored bird (Co-dominant w/E)

Gene 'C' is for long song (Dominant)
Gene 'c' is for short song (Recessive)

Gene 'B' is for high notes (Co-dominant w/b)
Gene 'b' is for low notes (Co-dominant w/B)

Gene 'F' is resistant to disease (Dominant)
Gene 'f' is susceptible to disease (Recessive)

Gene 'x' is for other traits

The example of chromosome pair 1 shows that if a breeder only breed for a pure flute sound (Gene 'd') the gene pair would only have open beak phrases and would be undesirable. This happens because Gene 'd' is on the same chromosome as Gene 'A', they are 'linked' together. If the breeder bred for closed beak phrases he would eliminate the flute sounds. In this example the best thing to do is to compromise and have both genes 'D' and 'd' be present since they are co-dominant and would have an in-between sound and may add more variety.

Chromosome pair 2 shows an example of maybe why so many of the winners are self or foul birds. If a breeder bred for longer song (Gene 'C') he would eventually eliminate the clear colored trait ( Gene 'e') and have only self colored birds. This can explain why birds in a certain line shows common markings even though this was not intentional.

Chromosome pair 3 shows how some highly inbred strain can have weak traits. If low notes (Gene 'b') are focused on, this strain of birds could be very weak due to the concentration of Gene 'f' since they are linked together on the same gene. It would be best to have a compromise on this chromosome pair.

To prevent a trait from being lost it would be advisable to have several separate lines of American Singers. On each line you can have a different goal toward the type of song you want. For example: louder, softer, more flute, more roll, etc. This way you don't commit all of your birds to a goal that may lose a desirable trait. You can then recover a trait if your other lines still carry it.

Copyright © 1997 Bryan Chin. All rights reserved.

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