SV to Reinstate Long Coats in 2010 - Page 12

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darylehret

by darylehret on 07 April 2008 - 19:04

The purpose of Hardy Weinberg principle isn't to measure number of alleles or diversity of a locus. It is simply to determine expected frequencies of two alleles at a given locus.

That's what I'm asking, can HWE measure a locus that has more than two possible alleles?

There's no way that a single breed could have a higher genetic diversity than a collective group including that breed. 

I would disagree, for example, in the case of isolated populations. But it is a very good point to make, that it is unknown whether the samples taken were from american line, german line, czech line, showline, workingline, DDR line, or a line rumored to have been crossed with mals, wolves, or what have you, or how related these samples may have been to each other..

 


pod

by pod on 07 April 2008 - 22:04

"That's what I'm asking, can HWE measure a locus that has more than two possible alleles?"

You couldn't do more than two alleles in one calculation but you could do separate calculations for each allele paired with the wild type I suppose.  You would then have distinct HW assessments for each allele.  But the whole point of using SNPs for HW calculation is that they have only two alleles per locus, presumably to make the process simple.

"I would disagree, for example, in the case of isolated populations."

I can't see how it would be possible in any population.  If you include the the whole gene complement of the first sample (say Min Poodle) and add it too the rest of the group (Standard and Toy) you have to be increasing the gene diversity.  There's no way it could be any different.

"But it is a very good point to make, that it is unknown whether the samples taken were from american line, german line, czech line, showline, workingline, DDR line, or a line rumored to have been crossed with mals, wolves, or what have you, or how related these samples may have been to each other.."

Yes, it does seem that in certain breeds/groups, the more diverse the phenotype, the more likely there is to be high disequilibrium.  The study does indicate a strong negative correlation between diversity and HWE.

 


pod

by pod on 07 April 2008 - 23:04

"I can't see how it would be possible in any population."

Ok, I've had a rethink.  There is a possible way, though it's very, very unlikely to occur in reality.  But I would like to hear your proposition first Daryl

 


darylehret

by darylehret on 07 April 2008 - 23:04

My immediate line of thought was, the data is not useful for myself if it doesn't exclude the showlines, as I have little intention of utilizing them in my breeding.  I would like to see figures that take into consideration the subsets we use, sort of how OFA hip results represent the entire breed, but many would suspect the showlines to be higher contributors of HD.


by Speaknow on 08 April 2008 - 08:04

Daryl, you say: “The data [HW Equilibrium] is not useful for myself if it doesn't exclude the show-lines, as I have little intention of utilizing them in my breeding.” I’m curious to know how you’d use HWE data in any sort of practical way at all! Particularly since one of its most crucial premises – the need for a random-mating population - simply doesn’t hold true. And as this thread relates to long-coats and any possible loss in genetic diversity were they eliminated, how is any of it relevant? By contrast, mentioned inbreeding co-efficient, as derived from pedigree as for the one devised by Wright, has a meaningful and wider practical value (various software packages generate requisite inbreeding percentages for whole databases at one.) The link you gave above and data shown is thus primarily aimed at disclosing the validity of using different breeds for purposes of human research. Thus: “These characteristics are important for association mapping of candidate genes for diseases and therefore make dogs ideal models for gene mapping of human disorders. The isolation and small effective population size of modern breeds has resulted in widespread inbreeding and the expression of a large number of genetic diseases. Many of these are also among the most frequently occurring diseases in humans, such as cancer, heart problems, deafness, blindness and joint diseases. The partitioning of genetic diversity into discrete classes (breeds) has made the dog an exceptional model for the study of the association between genotype and phenotype and for the identification of genes involved in phenotypic and behavioral traits or diseases.” Also, HW Law merely promises that gene frequencies and genotype proportions in such a population remain constant from generation to generation, and that included recessive genes will persist no matter how small their representation. It further assures, for as long as underlying requirements remain in force anyway, that populations are able to retain a reserve of variability, or those genes without any current selective worth that is, so that if future conditions change, the gene pool is accordingly able to adapt. Were it otherwise, with recessives steadily removed, the population would soon become homozygous. By the way, is it possible for a sub-population to be genetically more diverse without abrogating at least one of HWE fundamental underpinnings?

darylehret

by darylehret on 08 April 2008 - 12:04

There's a useful context for any information, and I won't discuss it, if I'd quit getting asked about it.  Next thing y'know, this'll be a thread about my spelling mistakes!  Start a new thread, and go from there.


by Speaknow on 10 April 2008 - 07:04

Classic, Daryl! First you throw this thread into irrelevant direction with interest in HWE (with me wondering why you hadn’t initiated a new one but playing ball anyway), and then, the instant you’re asked the simplest of questions on a matter you raised to begin with, you cite “context” and suggest starting a new topic! I’ll start a new one, ‘The Need For Genetic Diversity’, but despite its importance to Breed’s future, doubt it will make for much interest: those to do with people, factional controversy or superficial trivia are what really score the hits!

darylehret

by darylehret on 13 April 2008 - 06:04

And as this thread relates to long-coats and any possible loss in genetic diversity were they eliminated, how is any of it relevant?~Speaknow

Diversity is NOT important for this breed's future, PRIORITIZED breeding is.  HWE samples on a few gsd's of unspecified population "pockets", is totally useless information.  So why carry on about it, anyway?






 


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