weismann disproved the idea of inheritance using tailless mice.
weismann disproved the idea of inheritance using tailless mice.
who disproved the idea of inheritance using tailless mice?
weismann
darwin's pangenesis theory was widely criticised, in part for its lamarckian premise that parents could pass on traits acquired in their lifetime. conversely, the neo-lamarckians of the time seized upon pangenesis as evidence to support their case. italian botanist federico delpino's objection that gemmules' ability to self-divide is contrary to their supposedly innate nature gained considerable traction; however, darwin was dismissive of this criticism, remarking that the particulate agents of small pox and scarlet fever seem to have such characteristics. lamarckism fell from favour after august weismann's research in the 1880s indicated that changes from use (such as lifting weights to increase muscle mass) and disuse (such as being lazy and becoming weak) were not heritable. however, some scientists continued to voice their support in spite of galton's and weismann's results: notably, in 1900 karl pearson wrote that pangenesis "is no more disproved by the statement that 'gemmules have not been found in the blood,' than the atomic theory is disproved by the fact that no atoms have been found in the air." finally, the rediscovery of mendel's laws of inheritance in 1900 led to pangenesis being fully set aside. julian huxley has observed that the later discovery of chromosomes and the research of t. h. morgan also made pangenesis untenable.
pangenesis
to form the buneman graph for a set of species and characteristics, first, eliminate redundant species that are indistinguishable from some other species and redundant characteristics that are always the same as some other characteristic. then, form a latent vertex for every combination of characteristic values such that every two of the values exist in some known species. in the example shown, there are small brown tailless mice, small silver tailless mice, small brown tailed mice, large brown tailed mice, and large silver tailed mice; the buneman graph method would form a latent vertex corresponding to an unknown species of small silver tailed mice, because every pairwise combination (small and silver, small and tailed, and silver and tailed) is observed in some other known species. however, the method would not infer the existence of large brown tailless mice, because no mice are known to have both the large and tailless traits. once the latent vertices are determined, form an edge between every pair of species or latent vertices that differ in a single characteristic.
median graph