The Extended Synthesis: Something Old, Something New

The eclipse of Darwinism began to end in the 1980s and hangs in the balance today. We need an Extended Synthesis, using “extension” metaphorically. We must extend back in time to recover important aspects of Darwinism that were set aside, and then lost during neo-Darwinism, then move forward beyond neo-Darwinism to encompass new data and concepts. The most comprehensive framework for the Extended Synthesis is the Major Transitions in Evolution. The Extended Synthesis rests comfortably within a philosophical perspective in which biology does not need to be connected with other areas of science in order to justify itself. I am attracted to an older concept in which biology needs a covering law to connect it with the rest of the natural sciences. Darwin implicated a “higher law,” but did not specify it. If we can elucidate that law, the Extended Synthesis will become the Unified Theory of Biology called for by Brooks and Wiley 25 years ago.     

Something Old and Something New: An Update on the Amazing Repertoire of Bacteriocins Produced by Streptococcus salivarius

Streptococcus salivarius has an exclusive and intimate association with humans. We are its sole natural host, and its contribution to the relationship appears overwhelmingly benevolent. Beautifully adapted to its preferred habitat, the human tongue, it only rarely ventures far from this location in the healthy host and indeed appears ill-equipped to become invasive due to a scarcity of virulence attributes. We consider that its strategically advantageous lingual location and numerical predominance allow S. salivarius to carry out a population surveillance and modulation role within the oral microbiota. Some strains are armed with complex arrays of targeted antibiotic weaponry, much of which belongs to the lantibiotic class of bacteriocins and a key to their ability to assemble and utilize this armament is their possession of transmissible multi-bacteriocin-encoding megaplasmid DNA. This review traces the origins of research into S. salivarius bacteriocins and bacteriocin-like inhibitory substances, showcases some of the inhibitory activities that we currently have knowledge of, and speculates about potential directions for ongoing investigation and probiotic application of this previously under-rated human commensal.     

Careers: An Interview with Joan Woodbury

Abstract

Patrick Brantlinger. Bread and Circuses: Theories of Mass Culture as Social Decay. Ithaca, New York: Cornell University Press, 1988. 307 pages. $9.95 paperback. Reviewed by Samuel Hope     

Science Translator: An Interview with Louisa Stark

The Genetics Society of America’s Elizabeth W. Jones Award for Excellence in Education recognizes significant and sustained impact on genetics education. The 2015 awardee, Louisa Stark, has made a major impact on global access to genetics education through her work as director of the University of Utah Genetic Science Learning Center. The Center’s Learn.Genetics and Teach.Genetics websites are the most widely used online genetic education resources in the world. In 2014, they were visited by 18 million students, educators, scientists, and members of the public. With over 60 million page views annually, Learn.Genetics is among the most used sites on the Web.Open in a separate window     

Something Old and Something New: Wedding Recombinant Inbred Lines with Traditional Line Cross Analysis Increases Power to Describe Gene Interactions

In this paper we present a novel approach to quantifying genetic architecture that combines recombinant inbred lines (RIL) with line cross analysis (LCA). LCA is a method of quantifying directional genetic effects (i.e. summed effects of all loci) that differentiate two parental lines. Directional genetic effects are thought to be critical components of genetic architecture for the long term response to selection and as a cause of inbreeding depression. LCA typically begins with two inbred parental lines that are crossed to produce several generations such as F1, F2, and backcrosses to each parent. When a RIL population (founded from the same P1 and P2 as was used to found the line cross population) is added to the LCA, the sampling variance of several nonadditive genetic effect estimates is greatly reduced. Specifically, estimates of directional dominance, additive x additive, and dominance x dominance epistatic effects are reduced by 92%, 94%, and 56% respectively. The RIL population can be simultaneously used for QTL identification, thus uncovering the effects of specific loci or genomic regions as elements of genetic architecture. LCA and QTL mapping with RIL provide two qualitatively different measures of genetic architecture with the potential to overcome weaknesses of each approach alone. This approach provides cross-validation of the estimates of additive and additive x additive effects, much smaller confidence intervals on dominance, additive x additive and dominance x dominance estimates, qualitatively different measures of genetic architecture, and the potential when used together to balance the weaknesses of LCA or RIL QTL analyses when used alone.     

Unanticipated Success Stories: An Interview with Angelika Amon

THE Genetics Society of America Medal is awarded to an individual for outstanding contributions to the field of genetics in the past 15 years. Recipients of the GSA Medal are recognized for elegant and highly meaningful contributions to modern genetics. The 2014 recipient, Angelika B. Amon, has uncovered key principles governing the cell cycle and was the first to demonstrate a connection between the physical completion of anaphase and the initiation of mitotic exit. More recently, her research has focused on the consequences of aneuploidy. GENETICS spoke with Dr. Amon about her approach to science and what is next on the horizon.Open in a separate windowAngelika B. Amon