Journal ArticleDOI
Quantitative genetics and evolution: Is our understanding of genetics sufficient to explain evolution?
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TLDR
This bridge between genetics and other parts of biology shows that the various theories apparently causing concern for the modern synthetic theory of evolution are entirely compatible with it.Abstract:
ummary
We have provided a bridge between geneticists, who tend to concentrate on genes and their frequencies, and other biologists, who are much more aware of how severely the environment constrains and limits life. This bridge is the recognition that
a. fitness is a product of important component traits,
b. these and most other traits consume environmental resources and these resources are additively related and can sum to no more than the total resources an animal can obtain from the environment,
c. allele frequencies can alter only to the degree that the phenotypes that carry the alleles reproduce themselves successfully, i. e. are fit,
d. fitness must rise, because it is never free from natural selection upwards, to the point where it can rise no further, because all environmental resources available to an animal are being used most efficiently,
e. in this state of adaptation, fitness is completely limited by the environment and all other traits important to the animal are constrained to a greater or lesser degree at intermediate, “optimal” values, and
f. traits or molecules unimportant to animals, so that they are completely neutral with respect to fitness, are free to drift genetically and hence gene substitutions can occur at rates related to their mutation rates.
This bridge between genetics and other parts of biology shows that the various theories apparently causing concern for the modern synthetic theory of evolution are entirely compatible with it. Bursts of rapid evolutionary change between long periods of evolutionary stasis are the necessary consequences of strong natural selection acting on fitness, in ecosystems that are stable until external forces cause them to change. Neutral (random) evolution describes the fate of genetic material that is unimportant for organisms, i. e. material that is truly neutral with respect to fitness.
Zusammenfassung
Quantitative Genetik und Evolution. Genugt unser genetisches Verstandnis um Evolution zu erklaren?
Wir bauten eine Brucke zwischen Genetikern, die mit Genen und ihren Frequenzen arbeiten, und anderen Biologen, die wissen wie stark die Umwelt Lebewesen hemmend beeinflust. Diese Brucke besteht aus den folgenden Erkenntnissen:
a. Fitness ist ein Produkt der wichtigsten Komponenten.
b. Diese und die meisten anderen Merkmale verbrauchen Nahrung. Die Nahrung, die ein Lebewesen nur aus der Umwelt erhalten kann, enthalt die maximale Summe der metabolischen Ressourcen, die das Wesen dann in additiver Weise in einzelne Merkmale investiert.
c. Allelfrequenzen konnen sich nur erhohen, wenn der Phanotyp, der die Allele tragt, sich erfolgreich fortpflanzt.
d. Weil Fitness immer unter naturlicher Selektion nach oben steht, mus der Fitnesswert steigen bis alle Umweltressourcen so effizient wie moglich genutzt werden.
e. In solchem Stadium der volligen Anpassung an die Umwelt, ist Fitness ganz durch die Umwelt limitiert und alle anderen wichtigen Merkmale in groserem oder kleinerem Mase in Optimalwerte gezwangt.
f. Unwichtige Merkmale oder genetische Molekule, die keine Wirkung im Lebewesen haben, so das sie wirklich neutral sind gegenuber Fitness, durfen ungehemmt driften und zeigen deshalb Substitutionsraten, die ihren Mutationsraten entsprechen.
Diese Brucke zwischen Genetik und der ubrigen Biologie zeigt, das die Evolutionstheorien, die angeblich die moderne Evolutionssynthese storen, vollkommen mit ihr im Einklang sind. Sprungartige Evolution zwischen langen, stabilen Zeitraumen sind die Zwangsfolgen starker naturlicher Selektion auf Fitness in Okosystemen, die sich nicht andern bis ein Druck auserhalb des Systems das bewirkt. Neutrale Evolution beschreibt, was mit dem Material passiert, das unwichtig fur Lebewesen ist.read more
Citations
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Genetics of adaptation and domestication in livestock
Sandrine Mignon-Grasteau,Alain Boissy,Jacques Bouix,Jean-Michel Faure,Andrew D. Fisher,Geoffrey Hinch,Per Jensen,Pierre Le Neindre,Pierre Mormède,Patrick Prunet,Marc Vandeputte,Catherine Beaumont +11 more
TL;DR: The characteristics that favoured domestication are described, especially gregariousness, precocity of young and diet, and major behavioural modifications observed during domestication, including relationships with humans and predators, and social, feeding, reproductive and maternal behaviours as well as morphological changes.
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Domestication effects on foraging strategy, social behaviour and different fear responses: a comparison between the red junglefowl (Gallus gallus) and a modern layer strain
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References
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Journal ArticleDOI
Components of fitness become effectively neutral in equilibrium populations.
TL;DR: In this paper, the definition of neutrality is extended to include factors (genetic or phenotypic) that "behave as if they are neutral" and selectively important traits become subsumed under neutral traits.
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