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Category Archive for 'Trade-offs'

Altshuler and colleagues (Nature Genetics, 2014) recently reported a study of about 150,000 individuals representing five different ancestral groups in which they identified twelve low-frequency variants of the gene SLC30A8 through either genomic sequencing or genotyping.  These variants are all predicted to truncate the gene product (ZnT8), a protein involved in zinc transport in beta […]

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Epistasis refers to the influence of one genomic mutation or variant on the phenotypic effects of another mutation or variant.  Based on available evidence and theory, this phenomenon has a major influence on evolutionary trajectories for organisms of all sorts.  The role of epistasis has been studied primarily in the context of adaptive evolutionary change.  […]

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Toxoplasma gondii is an intracellular protozoan parasite that infects many different vertebrate species asexually and undergoes a sexual cycle after infecting cats (http://www.cdc.gov/parasites/toxoplasmosis/, 2013).  Parasite oocysts are potentially introduced into the human environment in cat feces.  T. gondii is of interest in clinical medicine because humans can serve as accidental intermediate hosts when they ingest […]

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Biomedical scientists and biologists routinely consider how selection shapes the structure and function of proteins of interest.  Less commonly, I suspect, do we consider how selection for attributes other than protein structure and function can favor or disfavor nucleotide sequences that encode particular amino acid sequences.   A new study (Stergachis et al., 2013) published in […]

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In his 1987 book, “The Evolution of Individuality,” Leo Buss addressed a fundamental biological question: “How could individual multicellular animals (known as metazoans), like sea anemones, insects, frogs, and humans arise?”  Buss focused on a key challenge confronting any multicellular animal with differentiated cell types performing different functions: the potential conflict between selection on the […]

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A central focus of recent research aimed at developing a vaccine for HIV-1 is the identification of potent broadly-neutralizing antibodies (bNAbs).  Due to work from several laboratories, many such antibodies have now been identified, produced in quantity as monoclonal antibodies, and characterized with respect to key properties such as epitope specificity, affinity for the corresponding […]

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The term “genetic code” is associated with a measure of ambiguity.  For molecular biologists, “genetic code” has historically referred to a table that provides for each messenger RNA ribonucleotide triplet the corresponding amino acid that is incorporated into the growing end of a nascent polypeptide chain, i.e. the translation from RNA sequence to protein sequence.  […]

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Influenza A viruses continue to be of enormous interest to biomedical researchers and clinicians alike.  In addition to the annual influenza epidemics, which have been inferred to cause substantial excess mortality, there is the ever-present threat of a global pandemic due to several features of influenza virus biology.  A high mutation rate associated with a […]

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  An interesting hypothesis in the evolutionary genetics of treating infections and cancers is that if the therapeutic agent does not directly target the pathogen or tumor, then the pathogen or tumor will be less likely to evolve resistance to that agent.  While early work on inhibitors of angiogenesis as potential cancer therapeutics suggested that […]

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Both Nature and Science are currently celebrating the 100th anniversary of the birth of an icon of logic, computer science, and mathematical biology: Alan Turing.  In reading Andrew Hodges’s spectacular biography of Turing (1983) many years ago I came to appreciate that the subject of the book was both a deeply creative and extraordinarily rigorous […]

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Natural selection depends on heritable phenotypic variation.  The most obvious source of phenotypic variation is genotypic variation.  A new study, by Casanueva et al. in Science (2012) suggests that in addition to genotypic variation, variation in life history and stochastic variations in gene expression can substantially affect phenotypic variation. These authors studied mutation penetrance in […]

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As noted in my last post, the selective advantage of heterozygosity for the sickle allele at the beta-globin locus has been known since Allison’s report in 1954 (Lancet).  Nevertheless, a plausible and detailed mechanism to account for the protective effect of an allele that is typically highly deleterious when homozygous has not been forthcoming until […]

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In previous posts, I discussed, respectively, the use of selection to generate an antibody of potential value in treating influenza A virus infections (1) and the relevance of protein dynamics to the evolution of protein function (2).   A recent paper in Science (3) offers evidence suggesting that internal protein dynamics play a crucial role in […]

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In an 1858 humorous poem The Deacon’s Masterpiece, or the Wondeful One Hoss Shay, Oliver Wendell Holmes Sr. described a carriage so artfully constructed as to have no weakest link. The carriage ran smoothly for exactly a hundred years, and then one day it went to pieces all at once, – All at once, and […]

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According to both academic lore and history  (Paulos, 1985; Ryerson, 2004), the late Sidney Morgenbesser, a professor of philosophy at Columbia and a renowned conversationalist and wit, was once listening to an Oxford colleague, J. L. Austin, lecturing on the philosophy of language.  The eminent Professor Austin proceeded to claim that while a double negative […]

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I recently saw the movie, “The Blind Side,” based on a book of almost the same name (“The Blind Side: Evolution of a Game”) by author, Michael Lewis. The reference to “evolution” in the book title refers to the adaptations necessitated in the (American) game of football on the offensive line, especially at the left tackle […]

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The human appendix has long fascinated both biologists and physicians. A recent bout of appendicitis has heightened my interest in this organ and has stimulated me to write about it. Because of its small and variable size, an The human vermiform appendix (image from the Talk Origins Archive; www.talkorigins.org) d its apparent uselessness, Darwin (1871) […]

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