Isolation breeds naivety : island living robs Australian varanid lizards of toad-toxin immunity via four-base-pair mutation

Since their introduction to the toad-free Australian continent cane toads (Bufo marinus) have caused a dramatic increase in naïve varanid mortality when these large lizards attempt to feed on this toxic amphibian. In contrast Asian–African varanids, which have coevolved with toads, are resistant to toad toxin. Toad toxins, such as Bufalin target the H1-H2 domain of the α1 subunit of the sodium-potassium-ATPase enzyme. Sequencing of this domain revealed identical nucleotide sequences in four Asian as well as in three African varanids, and identical sequences in all 11 Australian varanids. However, compared to the Asian–African varanids, the Australian varanids showed four-base-pair substitutions, resulting in the alteration in three of the 12 amino acids representing the H1-H2 domain. The phenotypic effect of the substitutions was investigated in human embryonic kidney (HEK) 293 cells stably transfected with the Australian and the Asian–African H1-H2 domains. The transfections resulted in an approximate 3000-fold reduction in resistance to Bufalin in the Australian HEK293 cells compared to the Asian–African HEK293 cells, demonstrating the critical role of this minor mutation in providing Bufalin resistance. Our study hence presents a clear link between genotype and phenotype, a critical step in understanding the evolution of phenotypic diversity.

On a neglected argument in French philosophy: Sceptical humanism in Montaigne, Voltaire and Camus

This paper wants to draw out a common argument in three great philosophers and littérateurs in modern French thought: Michel de Montaigne, Voltaire, and Albert Camus. The argument makes metaphysical and theological scepticism the first premise for a universalistic political ethics, as per Voltaire's: "it is clearer still that we ought to be tolerant of one another, because we are all weak, inconsistent, liable to fickleness and error." The argument, it seems to me, presents an interestingly overlooked, deeply important and powerful contribution to the philosophical discourse of modernity. On one hand, theological and post-structuralist critics of "humanism" usually take the latter to depend either on an essentialist philosophical anthropology, or a progressive philosophy of history. The former, it is argued, is philosophically contestable and ethically contentious (since however we define the human "essence," we are bound to exclude some "others"). The latter, for better or worse, is a continuation of theological eschatology by another name. So both, if not "modernity" per se, should somehow be rejected. But an ethical universalism - like that we find in Montaigne, Bayle, Voltaire, or Camus - which does not claim familiarity with metaphysical or eschatological truths, but humbly confesses our epistemic finitude, seeing in this the basis for ethical solidarity, eludes these charges. On the other hand, philosophical scepticism plays a large role in the post-structuralist criticisms of modern institutions and ideas in ways which have been widely taken to license forms of ethics which problematically identify responsibility, with taking a stand unjustifiable by recourse to universalizable reasons. But, in Montaigne, Voltaire and Camus, our ignorance concerning the highest or final truths does not close off, but rather opens up, a new descriptive sensitivity to the foibles and complexities of human experience: a sensitivity reflected amply, and often hilariously, in their literary productions. As such, a critical agnosticism concerning claims about things "in the heavens and beneath the earth" does not, for such a "sceptical humanism," necessitate decisionism or nihilism. Instead, it demands a redoubled ethical sensitivity to the complexities and plurality of political life which sees the dignity of "really-existing" others, whatever their metaphysical creeds, as an inalienable first datum of ethical conduct and reflection. After tracking these arguments in Montaigne, Voltaire, and Camus, the essay closes by reflecting on, and contesting, one more powerful theological argument against modern agnosticism's allegedly deleterious effects on ethical culture: that acknowledging ignorance concerning the highest things robs us of the basis for awe or wonder, the wellspring of human beings' highest ethical, aesthetic, and spiritual achievements.