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Andy Gardner - One of the best experts on this subject based on the ideXlab platform.
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Kin selection under Blending Inheritance
Journal of Theoretical Biology, 2011Co-Authors: Andy GardnerAbstract:Why did Darwin fail to develop his insights on kin selection into a proper theory of social adaptation? One suggestion has been that his inadequate understanding of heredity kept the problem out of focus. Here, I determine whether it is possible to develop a quantitative theory of kin selection upon the assumption of Blending Inheritance. I find that, whilst Hamilton's rule of kin selection can be readily derived under the assumption of Blending Inheritance, this mechanism complicates the computation of relatedness coefficients, and can even cause them to fluctuate over generations. Nevertheless, I show that the ultimate criterion for selection to favour any social trait - i.e. a time-average of Hamilton's rule - remains the same as under particulate Inheritance. By eliminating the gene from the theory of kin selection, I clarify the role that it plays in the theory of social adaptation.
Sydney Brenner - One of the best experts on this subject based on the ideXlab platform.
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A natural selection
Current biology : CB, 2000Co-Authors: Sydney BrennerAbstract:R.A. Fisher, in his 1929 book The Genetical Theory of Natural Selection, noted that Charles Darwin believed in the theory of Blending Inheritance, and that this conditioned his views on variation and therefore on theories for the possible causes of evolution. Darwin realized that Blending, or fusion, Inheritance reduces variation and that all variability must be continually at work, or else natural selection would have nothing to act upon. Thus, Blending Inheritance forced Darwin and others to attach great importance to hypothetical means of producing variability or, as we would see it now, there was a need for mutations to be arising all of the time, to defeat the inevitable regression to homogeneity.Darwin and his contemporaries were all Lamarckians. The arch-Lamarckian was, of course, Lamarck himself, who thought it was enough for animals to want to change and that the right mutations would be produced to satisfy these desires in their progeny. Darwin thought it was the adaptive changes themselves that triggered the mutations; others postulated evolutionary forces that acted from the outside, or intrinsic urges in organisms themselves.It was Mendel’s discoveries that dispelled all of this nonsense. Most people remember him for his laws of segregation, but it is his theory of particulate Inheritance that provided the fundamental basis for evolution by natural selection, and that enabled natural selection to be studied, not as the junior partner in Darwin’s theory, but as the central agency working with particulate Inheritance. As everybody knows, Mendel’s discoveries lay neglected and unknown until their rediscovery 100 years ago this year.I have gone into all of this because I become more and more conscious that most people do not understand evolution by natural selection. As direct evidence, I offer the following. A few months ago, an old friend, Jack Dunitz, reminded me that in 1994 I had signed a circular letter to do with journal publication, following which he had written to me under a pseudonym and that I still owed him a reply. I have no memory either of the circular or of receiving his letter. However, he was good enough to forward me a copy of his letter, and I reproduce it here together with my belated reply.Elysian FieldsBox 21Evolution DepartmentDecember 8, 1994Dear Dr Brenner,A circular letter signed by you and sent to several colleagues has recently been forwarded to me at the above address. You suggest a system in which editors go out of their way to select the best articles and papers for publication has some features in common with the theory of natural selection that I promulgated in the middle of the last century.I consider it my duty to inform you that such a system is totally contrary to the kind of selection process that I had in mind. In fact, you are appealing to the intervention of a higher being to select what is good and to reject what is bad. This is not at all what I had in mind.I regret very much that I did not make myself clearer and that you have misunderstood me in this important point.Yours faithfully,Charles DarwinThe AshesInferno Way, Fireproof Box 666HellMay 18, 2000Dear Charlie,I hope you get this reply which I have had printed on titanium sheets. I trust you recall that your theory included something that was outside organisms and which acted on them to exercise selection. This is the environment.In our circular, we simply suggested that editors should constitute an effective environment. Perhaps we did not make it clear enough, but it is reproductive success that is important. We were not interested in the papers — these constitute the phenotype; it is the survival of authors that is the key issue. Selection against certain papers would render their authors extinct; they would fail to get grants and gain promotion, and they would not train others. I suppose that with your dependence on Blending Inheritance and your failure to keep up with modern literature your complaint might be excused.You will note from my address that I have nothing to do with Supreme Beings. The same could not be said of you.Yours,Uncle Syd
Liu Jie - One of the best experts on this subject based on the ideXlab platform.
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Genetic analysis of seedling growth rate of cucumber under low temperature and weak light conditions.
2010Co-Authors: Yan Shijiang, Si Longting, Ma Zhiguo, Yang Jiaming, Zhang Jining, Zhang Jianjun, Liu JieAbstract:【Objective】 Heredity of chilling tolerance was analyzed in Cucumis sativus L.by carrying on low-temperature treatments.【Method】 In low-temperature treatments,i.e.12/8℃ in day/night,with 7.5 hours every day,and light intensity at 30 μmol·m-2·s-1 (or 2 klx) for 14 days,9507,9517 and their combinations BC1,BC2,F1,F2 and so on 6 generations,with different growth rates were used in experiment.The host gene-multi gene Blending Inheritance model method was used to study the genetic rule of growth rate,and estimate the genetic parameters.【Result】 The growth rate heredity was controlled by 2 pairs of additive – dominantmajor gene + additive-dominant multi-genes,and the 2 pairs of host genes additive effect were the same,the dominant effect was slightly different,the total additive effect was very big.The main gene + multigene heredity rate occupied an extremely large superiority,and the environment variance had very influence on phenotypic variance.【Conclusion】 Under the low temperature condition environment plays a very little role in the heredity of growth rate and it is suitable for the selection in early generation.
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Genetic analysis of major gene-multi genes of cucumber seedling MDA content in low temperature and weak light.
2009Co-Authors: Yan Shijiang, Zhang Jining, Liu JieAbstract:The materials of 9507,9517 and their BC1,BC2,F1,F2 were carried on low-temperature treatments,12/8℃ in day/night,with 7.5 h everyday by the light intensity of 30 μmol·m-2·s-1(or 2 000 lx) for 14 days,which were different in tolerance of low temperature and weak light.The genetic rule of MDA content was researched by the host gene-multi-genes Blending Inheritance model method,and the genetic parameter was also estimated.The results indicated that the MDA content inhereted with 2 pair of additive-dominant-epistasis major genes+additive-dominance multi-genes.The additive effect is the negative direction effect and the dominant effect also is the negative direction,the difference is not big.The total additive effect and the total dominant effect were negative direction.In the separation generation,the main gene heredity rate is higher than the multi-genes heredity rate,the environment variance synchronizing watches variance influence holds the absolute superiority.In other words,under the low temperature condition environment plays the very major role for the MDA content.The trait is suitable for the late generation selection regarding this character.
Michael Bulmer - One of the best experts on this subject based on the ideXlab platform.
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Did Jenkin's swamping argument invalidate Darwin's theory of natural selection?
The British Journal for the History of Science, 2004Co-Authors: Michael BulmerAbstract:Fleeming Jenkin's swamping argument (1867) is re-examined in relation to subsequent criticisms of its assumptions. Jenkin's original argument purported to show that, under Blending Inheritance, natural selection could not operate on ‘sports’ or ‘single variations’. A serious flaw in Jenkin's model was exposed in a forgotten paper in 1871. Darwin accepted Jenkin's ‘flawed’ conclusion, though he did not fully understand the argument. Both Jenkin and Darwin regarded the swamping argument as a barrier to evolution within a single lineage. A completely different interpretation of the phrase ‘swamping argument’, first put forward by Romanes in 1886, identified it with the problem of the role of free intercrossing in preventing speciation. The latter problem also underlies current debate about the possibility of sympatric speciation and is as serious under particulate as under Blending Inheritance. Jenkin's argument depended on the assumption of Blending Inheritance; when modified to remove the ‘flaw’ in his model, it ceased to present a barrier to the operation of natural selection within a lineage, provided that the mutation rate was high enough to maintain adequate genetic variability under Blending.
Yan Shijiang - One of the best experts on this subject based on the ideXlab platform.
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Genetic analysis of seedling growth rate of cucumber under low temperature and weak light conditions.
2010Co-Authors: Yan Shijiang, Si Longting, Ma Zhiguo, Yang Jiaming, Zhang Jining, Zhang Jianjun, Liu JieAbstract:【Objective】 Heredity of chilling tolerance was analyzed in Cucumis sativus L.by carrying on low-temperature treatments.【Method】 In low-temperature treatments,i.e.12/8℃ in day/night,with 7.5 hours every day,and light intensity at 30 μmol·m-2·s-1 (or 2 klx) for 14 days,9507,9517 and their combinations BC1,BC2,F1,F2 and so on 6 generations,with different growth rates were used in experiment.The host gene-multi gene Blending Inheritance model method was used to study the genetic rule of growth rate,and estimate the genetic parameters.【Result】 The growth rate heredity was controlled by 2 pairs of additive – dominantmajor gene + additive-dominant multi-genes,and the 2 pairs of host genes additive effect were the same,the dominant effect was slightly different,the total additive effect was very big.The main gene + multigene heredity rate occupied an extremely large superiority,and the environment variance had very influence on phenotypic variance.【Conclusion】 Under the low temperature condition environment plays a very little role in the heredity of growth rate and it is suitable for the selection in early generation.
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Genetic analysis of major gene-multi genes of cucumber seedling MDA content in low temperature and weak light.
2009Co-Authors: Yan Shijiang, Zhang Jining, Liu JieAbstract:The materials of 9507,9517 and their BC1,BC2,F1,F2 were carried on low-temperature treatments,12/8℃ in day/night,with 7.5 h everyday by the light intensity of 30 μmol·m-2·s-1(or 2 000 lx) for 14 days,which were different in tolerance of low temperature and weak light.The genetic rule of MDA content was researched by the host gene-multi-genes Blending Inheritance model method,and the genetic parameter was also estimated.The results indicated that the MDA content inhereted with 2 pair of additive-dominant-epistasis major genes+additive-dominance multi-genes.The additive effect is the negative direction effect and the dominant effect also is the negative direction,the difference is not big.The total additive effect and the total dominant effect were negative direction.In the separation generation,the main gene heredity rate is higher than the multi-genes heredity rate,the environment variance synchronizing watches variance influence holds the absolute superiority.In other words,under the low temperature condition environment plays the very major role for the MDA content.The trait is suitable for the late generation selection regarding this character.