Keeping mutations genetically strong - excellent clear info

[Finchy]

I came across a blog entry about why pedigree dogs have, genetically and health-wise, gone to hell in a hand basket. It's extremely well explained and informs every kind of animal breeding, so made me think of blue Gouldians and other mutations we enjoy. It explains in simple technical terms why it is so critical to be patient when developing any line of animals/birds, using a diverse foundation population and then adding entirely unrelated animals/birds to the line on a regular basis thereafter, even when this appears to mess things up temporarily.

The story begins like this:

1) All the useful genetic variation your breed[mutation] will ever have was in the dogs[birds] that founded the breed[mutation]. This genetic diversity is finite.

2) Every generation, alleles are lost by chance (genetic drift) and also by artificial selection by breeders, who select for dogs[birds] with the traits they like, and remove other dogs[birds] from the breeding population.

...the other 15 points are here, starting half way down the page: http://pedigreedogsexposed.blogspot.com ... pitch.html

Enjoy!

[Diane]

If you are interested in further reading I have a google page of Linebreeding articles, a page on Hybrid vigor, and 4 more websites on different theories of population and genetics that Im currently working my way through.

[Red]

6) You cannot select for or against a single gene, because genes tend to move in groups with other genes. If you select for (or against) one, you select for (or against) them all.

Not true. If I wanted to remove the white allele from my canary flock I would simply remove all the white birds. Crossing over events etc during meiosis ensure that you can indeed select for or against individual traits and the genes that produce them. Just because gene A and gene B are on the same chromosome in the parent, it does not follow that they will both be present together in the offspring.

Surely those breeding for colour traits are not limited to a closed studbook like some pedigree dog breeders are. I don't think any finch breeders face the serious medical problems that dog breeders were seen to deal with in the film "Pedigree dogs exposed".

[finchbreeder]

Unless breeding a mutation in a non aussie finch that is in low numbers, we should not face the same degree of problems. But it never hurts to think about how to avoid problems before they happen.
LML

[Myzomela]

Unless breeding a mutation in a non aussie finch that is in low numbers, we should not face the same degree of problems

You would think not but from what I have seen of some of the parrot mutations lately I wonder.
Show budgies have been plaqued with health & fertility problems for years through poor selective breeding. Cockatiels these days are only a shadow of what they used to be and don't have the vigour or longevity that they used to.
It is true that parrot mutations are more dollar driven and so people take short cuts to get as many coloured birds bred before the price drops.
Consequently many undersized and poor specimens are out there.
Most finch breeders do the hard work to strengthen their birds before being released into general aviculture but it is important to be vigilant.
Practices such as what has happened with the white longtails/parsons means that we need to be aware of what is happening and decide whether we agree with the ethics of some of these practices and with the genetic consequences that result ( be it inbreeding depression or hybridisation & bastardisation of the gene pool).

[Red]

On Exhibition Budgerigars, I think that the Miniature Budgerigar Society of Australasia has the right idea. Breeding birds whose eyes are clear of feathers is a positive thing.

I should say however that the miniature budgerigar standard is different from the true bush budgie type:

https://sites.google.com/site/miniature ... d-policies

[finchbreeder]

If those pics are meant to be the standard for miniture budgies, they are just a smaller version of the types that were show standard some 15/25 years back. My memory is a bit uncertain of time frame.
Sorry Myzo I was not refering to birds in general with my comments, only finches specifically. Yes there are problems in hookbills where people are considering cash ahead of health. Or ribbons ahead of colour, health and type balance.
LML