A very interesting programme on the problem of inbreeding with pedigree dogs has recently been shown on BBC 1 in the UK; “Pedigree dogs exposed,” Tuesday 19th August 2008 21.00 BST. Although this programme didn’t set out to be anti Darwinian, there are some very interesting observations that come out of it that are really quite damaging to neo-Darwinian explanations. In fact the programme stated that the whole concept of purebred dogs came out of the eugenics movement of the 19th century.
It would seem that some breeds of dogs are so inbred that genetic defects are becoming a major problem, and are in fact leading to great suffering for the dogs. A related study by scientists at Imperial College London has shown that the 20,000 strong population of Boxer dogs has the genetic information of only 70 animals, the 12,000 Rough Collie’s contain the genetic information of only 50 dogs. See also:
Calboli FC , Sampson J, Fretwell N, Balding DJ, “Population structure and inbreeding from pedigree analysis of purebred dogs,” Genetics, 179(1): 593–601, 2008. doi:10.1534/genetics.107.084954
Two observations come out of this. Firstly, a great deal of morphological change can occur in a short period of time and yet not turn a dog into something that isn’t a dog. Changes in size, shape, colouration etc. occur, but still they are dogs, while the gene pool becomes ever more focussed on a few individuals. Large changes can occur by isolating and expressing pre-existing genetic information in a species without generating new information.
Secondly, the compounding of harmful mutations is a major problem for inbreeding in small populations in the wild, so much so that it risks the viability of the breed / species itself. The problems association with the tumours that develop on the faces of Tasmanian Devils is a case in point. And yet evolutionists will say that such small inbreeding populations have been an important part of the evolutionary process. The evidence suggests a different account, as it would constantly place evolving animals on the edge of extinction. Evolutionists will of course claim that artificial selection is not the same as natural selection because natural selection will weed out the unfit animals whereas human breeders don’t. But even that doesn’t help much as Haldane’s paradox highlights. Beneficial mutations are much rarer than harmful ones, and are more likely to be found in very large populations. But small, or isolated populations are required to get those mutations to spread through a population. The speed at which mutations become fixed in a population must also be sufficiently slow to weed out the far more numerous harmful mutations. Evolution then would require at the same time the benefit of very large populations and very small ones – without the overwhelmingly observed side effects that develop from compounding harmful mutations in small populations. Thus the gene pool of large populations cannot change much at all over time; while the gene pool of very small inbreeding populations in fact degrades making the species less fit overall.
It’s worth reading the Question Darwin blog for a more complete review of the evidence presented in the programme. Darwin Blog – Pedigree dogs, Genetic Entropy and Denial
Some video clips are available on the BBC website.
Video Clip 1
Video Clip 2
Video Clip 3
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6 Replies to “Pedigree dogs – or mutant monsters?”
“Beneficial mutations are much rarer than harmful ones, and are more likely to be found in very large populations. But small, or isolated populations are required to get those mutations to spread through a population.”
“The evidence suggests a different account, as it would constantly place evolving animals on the edge of extinction.”
All ‘modern’ dog breeds are defective in some degree -> the hallmark of Darwinian microevolution.
Even worse is that the “breed standards” for showing these pedigrees actually proscribe defective anatomy as ‘correct’. E.g. in German Shephards it is ‘more correct’ to have low slung back hips , despite this predisposing the dogs to Hip Dysplasia in later life, something the breed is already susceptible to. Brachycephalic breeds (squashed face) are even worse, possessing restricted airways, excessive pharyngeal folds, narrow nostrils, etc, which cumulates in respiratory difficulty – for no other reason than being of that breed. These dogs have to have their airways/noses surgically corrected to breath properly.
Anyway, working with the information in the title post, I guess the new format for establishing new mutations would have to be:
1) large population where the rare positive mutations can arise
2) animal(s) with the rare positive mutation are then segregated into a smaller population (by natural causes, of course) for the mutation to become established.
3) small population with positive mutation then spreads out/hybrids/etc to counter inbreeding lest they become less fit and are selected against, whilst maintaining the positive mutation.
But then this all depends on what we mean by ‘positive’ mutations – are we talking longer noses or new proteins/genetic instructions? As is thought, the former is easy to accomplish, the latter…
In the United States, the main problem is the AKC, which won’t allow the very outbreeding that created the breeds in the first place.
The major problem with the AKC, Crufts and ANKC (Australia), is that their focus is on arbitrary points of conformation and appearance, rather than on temperament and the welfare/health of the dog. Sure, it is in there, but if you’ve ever seen or been involved in judging the emphasis is on the superficial appearance of the dog.
If the focus shifted to rest heavily on healthy conformation and mentality, then there would be less stricture regarding outbreeding or altering the breed standards. I cannot comment on the AKC or Crufts, but the ANKC is shifting towards less superficial breed standards.
The documentary was also reported on down here in Aus: http://www.news.com.au/courier.....72,00.html
Sounds to me that this is inconclusive–as are most debates about Artificial vs. Natural selection. Breeding can create large structural differences in a small amount of time, but the selection is more about what looks cool to humans rather than what is functional.
So the straight evolutionists have a case that large differences can happen in a short span–but are left without comparisons. The intent of the humans is a major force in the time frame. We have an x-factor for acceleration.
ID seems to have a point about breeding weaknesses, but as Avonwatches expresses they are selected in some cases for “attractive” deformities. Kind of the way that the Chinese used to bind women’s feet–resulting in the small feet that they liked, but leaving them less than fully functional. The human intervention also messes up anything that applies directly to the effects of natural inbreeding.
It reminds me of something I was musing over recently: Materialists will use what they can to talk about the human brain as some kind of apparatus with resemblances to a computer. Then when pointed to the massive limitations on Turing Machines by computational theory, proclaim that there is no definite binding between a human brain and a Turing machine: they could be “another kind” of processing apparatus, ignoring any previous attempt to link the two. There is not at that point anything but a functional category: both process information. One of them in a much more elementally limited fashion.
It’s kind of odd when your opponent wants to make two conflicting points in a pedantic manner, simply to pretend to know more than he is willing to accept that we know.
From the documentary:
This is common as well, with Dalmations and Rottweiller breeds. I know firsthand, having had a dalmation that went berserk in middle life, and had to be euthanized.