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Apparently the first use of the term "Haldane's dilemma" was by paleontologist Leigh Van Valen in his 1963 paper "Haldane's Dilemma, Evolutionary Rates, and Heterosis". Van Valen writes: [8] Haldane (1957 [= The Cost of Natural Selection]) drew attention to the fact that in the process of the evolutionary substitution of one allele for another ...
In humans, barring intersex conditions causing aneuploidy and other unusual states, it is the male that is heterogametic, with XY sex chromosomes.. Haldane's rule is an observation about the early stage of speciation, formulated in 1922 by the British evolutionary biologist J. B. S. Haldane, that states that if — in a species hybrid — only one sex is inviable or sterile, that sex is more ...
Haldane's article on abiogenesis in 1929 introduced the "primordial soup theory", which became the foundation for the concept of the chemical origin of life. He established human gene maps for haemophilia and colour blindness on the X chromosome, and codified Haldane's rule on sterility in the heterogametic sex of hybrids in species.
The masking effect of outcrossing is known as genetic complementation, [3] an effect also recognized as hybrid vigor or heterosis. Once outcrossing is established in a lineage of flowering plants due to the benefit of genetic complementation, subsequent switching to inbreeding becomes disadvantageous because it allows expression of the ...
Haldane's dilemma regarding the cost of selection was used as motivation by Kimura. Haldane estimated that it takes about 300 generations for a beneficial mutation to become fixed in a mammalian lineage, meaning that the number of substitutions (1.5 per year) in the evolution between humans and chimpanzees was too high to be explained by ...
Heterosis or hybrid vigor, on the other hand, is the tendency of outbred strains to exceed both inbred parents in fitness. Selective breeding of plants and animals, including hybridization, began long before there was an understanding of underlying scientific principles.
Life Cycle of the Snapping Turtle. Snapping turtles mate in the water, and then the female will climb up onto sandy shores to lay her eggs in a hole she has dug in the sand. She lays dozens of ...
Pages in category "Works by J. B. S. Haldane" The following 6 pages are in this category, out of 6 total. ... Haldane's dilemma; Haldane's rule; O. On Being the Right ...