Showlines and Workinglines are Genetically Different - Interesting Study - Page 6

LOL, Gustav! Don't worry, the fever is up to 102 degrees, so anything I spout tonight is going to be nonsense! 

Wish I had some beer, or whiskey, then I show you how out to lunch I can really be!        (they say your eyes go like this when you're drunk, that's how the cops can tell, even without a breath test!)

Hope you're feeling better soon. I think there are some here who want to hear reason and learn about canine genetics. 

Thanks, Blitizen! If I could go back to university, genetics would be the area I would most like to take a refresher course in, as SOOO much has changed since I graduted in the 1970's!

LOL, when it goes much beyond simple recessives I have to really think hard when I don't have flu.There seems to be a lot more interest in canine genetics these days; mostly as a result of attempting to identify the markers for specific diseases I think. That's a good thing.

Take care......

Hope you are feeling better soon, Sunsilver. The plague has also gotten to our house, but luckily I'm the only one who doesn't have it *knocking on wood!!!*.

Thanks Sunsilver, one thing caught my attention in the study that breeders might benefit from but it doesn't really make much sense as per present facts. Study says that the crossed show lines with working lines are closer in genetic make up to working lines, but what we know is in phenotype the show lines are more homogenous than the working type and the type was set through many generations of selection for the type "phenotype". On the other hand the phenotype in working line dogs is not homogenous and variation is much bigger. So logically when crossing a showline with a working line the resultant dog should be closer in genetic build "at least in phenotype" to the show line parent and that is what we see in reality but the study says the opposite, it doesn't make sense, does it?!!!!!!!!! 

Sunsilver,

It is difficult for me to speak my thoughts in this regard as I studied biology at school in Arabic but I would like to highlight this, Different Genetic Build should not be mixed with Genes Variation. Please take note that in each species there is a basic genetic build for each and all of those that belong to the species. Also there are variations between the members of the species, each one is unique and there will never be 100% copies in a certain species and that is why for example in humans you find differences between brothers and between sisters but in biological science that is called genetic VARIATION not different GENETIC BUILD.

Nations, there are genetic variations between peoples, that is called GENETIC VARIATION not DIFFERENT GENETIC BUILD. First Human and present human have same GENETIC BUILD. 
Selective breeding, in selective breeding we save certain favourable traits or certain favorable phenotype and in a considerable designed number of generations we come up with a strain or even a breed but GENETIC BUILD will always be same it will never change and that is why all dogs have same GENETIC BUILD no matter what various breeds human created.
I agree that showlines may be considered by some as having different traits and different phenotype and might as well be called a seperate breed but I do not agree that they have a different GENETIC BUILD, because it is same as that of work line, also same as that of Rotts etc. The term "genetically different" should not be used to mean and should not be understood as "Different Genetic Build" in my opinion.
We should ask our selves two questions, would seperating the work and show into two breeds benefit the breed, my answer is absolutely NO, diversity in a breed is a good thing, narrowing the breed is not a right thing to do, those who ask for seperation in my opinion are politically driven not (biologically).
Second question, is biologically proving there are genetic variations between work and show a new thing, my answer is No, genetic variation is there in any and all species, also in any and all groups within a species but if some mixed genetic variation with different Genetic build then please don't. 

We should decide whether the genetic variation or as called (genetically different) is that big to justify considering them two different groups/breeds, my answer would be absolutely not, huge (genetic differences) takes place over hundreds of years not in few non-designed generations. Please note I put genetic differences in between brackets as I think it is a wrong term in describing differences between show and work.

From Wikipedia

Genetic diversity, the level of biodiversity, refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary.

Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals.^[1]

The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitutions. Diversifying selection is the hypothesis that two subpopulations of a species live in different environments that select for different alleles at a particular locus. This may occur, for instance, if a species has a large range relative to the mobility of individuals within it. Frequency-dependent selection is the hypothesis that as alleles become more common, they become more vulnerable. This in host-pathogen interactions, where a high frequency of a defensive allele among the host means that it is more likely that a pathogen will spread if it is able to overcome that allele.

Biodiversity is the degree of variation of life forms within a given species, ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions support fewer species.

Rapid environmental changes typically cause mass extinctions. One estimate is that less than 1% of the species that have existed on Earth are extant.^{[1][verification needed]}

Since life began on Earth, five major mass extinctions and several minor events have led to large and sudden drops in biodiversity. The Phanerozoic eon (the last 540 million years) marked a rapid growth in biodiversity via the Cambrian explosion—a period during which the majority of multicellularphyla first appeared.^[2] The next 400 million years included repeated, massive biodiversity losses classified as mass extinction events. In the Carboniferous, rainforest collapse led to a great loss of plant and animal life.^[3] The Permian–Triassic extinction event, 251 million years ago, was the worst; vertebrate recovery took 30 million years.^[4] The most recent, the Cretaceous–Paleogene extinction event, occurred 65 million years ago and has often attracted more attention than others because it resulted in the extinction of the dinosaurs.^[5]

The period since the emergence of humans has displayed an ongoing biodiversity reduction and an accompanying loss of genetic diversity. Named the Holocene extinction, the reduction is caused primarily by human impacts, particularly habitat destruction. Conversely, biodiversity impacts human health in a number of ways, both positively and negatively.^[6]

The United Nations designated 2011-2020 as the United Nations Decade on Biodiversity.

Genetic variability is a measure of the tendency of individual genotypes in a population to vary from one another. Variability is different fromgenetic diversity, which is the amount of variation seen in a particular population.^[1] The variability of a trait describes how much that trait tends to vary in response to environmental and genetic influences.^[1] Genetic variability in a population is important for biodiversity,^[2] because without variability, it becomes difficult for a population to adapt to environmental changes and therefore makes it more prone to extinction.

Variability is an important factor in evolution as it affects an individual's response to environmental stress and thus can lead to differential survival of organisms within a population due to natural selection of the most fit variants. Genetic variability also underlies the differential susceptibility of organisms to diseases and sensitivity to toxins or drugs — a fact that has driven increased interest in personalized medicinegiven the rise of the human genome project and efforts to map the extent of human genetic variation such as the HapMap project.

Population genetics is the study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow. It also takes into account the factors of recombination, population subdivision and population structure. It attempts to explain such phenomena as adaptation and speciation.

Population genetics was a vital ingredient in the emergence of the modern evolutionary synthesis. Its primary founders were Sewall Wright, J. B. S. Haldane and R. A. Fisher, who also laid the foundations for the related discipline of quantitative genetics.

Traditionally a highly mathematical discipline, modern population genetics encompasses theoretical, lab and field work.

The neutral theory of molecular evolution states that the vast majority of evolutionary changes at the molecular level are caused by random drift of selectively neutral mutants (not affecting fitness).^[1] The theory was introduced by Motoo Kimura in the late 1960s and early 1970s. Neutral theory is compatible with Darwin's theory of evolution by natural selection: adaptive changes are acknowledged as present and important, but hypothesized to be a small minority of all the changes seen fixed in DNA sequences.^[2] Since then, this hypothesis has been tested using the McDonald-Kreitman test, and has not been supported in all species.^[3] Even in those species in which adaptive changes are rare, background selection at linked sites may violate neutral theory's assumptions regarding genetic drift.^[4]


Disruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, thevariance of the trait increases and the population is divided into two distinct groups.^[1][2] Thisevolutionary process is believed to be one of the main driving forces behind sympatricspeciation.^[3]

Frequency-dependent selection is the term given to an evolutionary process where the fitness of a phenotype is dependent on its frequency relative to other phenotypes in a given population.

• In positive (or diversifying) frequency-dependent selection, the fitness of a phenotype increases as it becomes more common.

• In negative (or purifying) frequency-dependent selection, the fitness of a phenotype increases as it becomes rarer. This is an example ofbalancing selection.

Frequency-dependent selection is usually the result of interactions between species (predation, parasitism, or competition) or between genotypes within species (usually competitive or symbiotic), and has been especially frequently discussed with relation to anti-predator adaptations. Frequency-dependent selection can lead to polymorphic equilibria which result from interactions among genotypes within species, in the same way that multi-species equilibria require interactions between species in competition (e.g. where α_ij parameters in Lotka-Volterracompetition equations are non-zero).

 

I just spend three hours figuring out why my PCR did not produce what I wanted it to produce, I come here and you are discussing this?! Shame on you.....
Definitions are fine, theoretically, yes it can be possible as some mutations could have been the part of the selective breeding preferences. Of course they are genetically diferent, we ALL ARE! even if it is just only 0.1%!



So guys... how do you like the thought of Mitochondial DNA showing traces of paternal DNA... now that is a nice smack into ones theory, isnt it!