Evolving genomic metaphors: a new look at the language of DNA.

Recent genome-sequencing efforts have confirmed that traditional "good-citizen" genes (those that encode functional RNA and protein molecules of obvious benefit to the organism) constitute only a small fraction of the genomic populace in humans and other multicellular creatures. The rest of the DNA sequence includes an astonishing collection of noncoding regions, regulatory modules, deadbeat pseudogenes, legions of repetitive elements, and hosts of oft-shifty, self-interested nomads, renegades, and immigrants. To help visualize functional operations in such intracellular genomic societies and to better encapsulate the evolutionary origins of complex genomes, new and evocative metaphors may be both entertaining and research-stimulating

Phylogeography: Retrospect and prospect

Phylogeography has grown explosively in the two decades since the word was coined and the discipline was outlined in 1987. Here I summarize the many achievements and novel perspectives that phylogeography has brought to population genetics, phylogenetic biology and biogeography. I also address future directions for the field. From the introduction of mitochondrial DNA assays in the late 1970s, to the key distinction between gene trees and species phylogenies, to the ongoing era of multi-locus coalescent theory, phylogeographic perspectives have consistently challenged conventional genetic and evolutionary paradigms, and they have forged empirical and conceptual bridges between the formerly separate disciplines of population genetics (microevolutionary analysis) and phylogenetic biology (in macroevolution). © 2008 The Author

Genetics of plate morphology in an unusual population of threespine sticklebacks (Gasterosteus aculeatus)

A collection of Gasterosteus aculeatus from a single locality (Friant) in Madera County, California, contains individuals with low and high lateral plate morphology, and very few intermediates. Electrophoretic evidence on protein similarities at 15 genetic loci is compatible with the thesis that members of these two morphs belong to a single interbreeding population. This thesis is also supported by broods from laboratory crosses between morphs, which segregate for low and high plate counts. Laboratory crosses between Friant fish and those from geographically isolated populations often yield some progeny with intermediate plate counts. The demonstration of significantly different patterns of plate development in intralocality versus interlocality crosses evidences a contrasting genetic basis for plate determination in different populations of sticklebacks. © 1976, Cambridge University Press. All rights reserved

Considerations on the evolution of qualitative multistate traits

Simple models for the evolution of qualitative multistate traits are considered, in which the traits are permitted to evolve in time-dependent versus speciation-dependent fashion. Of particular interest are the means and variances of distances for these traits in evolutionary phylads characterized by different rates of speciation, when alternative characters are neutral with respect to fitness, and when the total number of observable characters is limited to small values. As attainable character states are increasingly restricted, mean distance (D) in a phylad decreases, regardless of whether evolution is a function of time or of rate of speciation. The ratio of mean distances in species-rich and species-poor phylads of comparable evolutionary age (DR/DP) remains near one when differentiation is proportional to time, even when attainable character states are severely restricted. DR/DP also nears one as a result of restricting character states when differentiation is proportional to rate of speciation, but the effect is not severe unless the number of character states is very small and the probability of change per speciation very large. These and other results are discussed with reference to available data sets on qualitative multistate traits. © 1979 Leiden University Press

A role for molecular genetics in the recognition and conservation of endangered species.

Taxonomies based on morphological traits alone sometimes provide inadequate or misleading guides to phylogenetic distinctions at the subspecies and species levels. Yet taxonomic assignments inevitably shape perceptions of biotic diversity, including recognition of endangered species. Case histories are discussed in which the data of molecular genetics revealed prior systematic errors of the two possible kinds: taxonomic recognition of groups showing little evolutionary differentiation, and lack of taxonomic recognition of phylogenetically distinct forms. In such cases, conservation efforts for 'endangered species' can be misdirected with respect to the goal of protecting biological diversity

Conservation genetics in the marine realm

Techniques for DNA and protein assay make possible genetic studies on any species. In recent years, molecular methods have been applied to a number of conservation-relevant genetic issues for marine organisms ranging from zooplankton to whales. To introduce these symposium proceedings, I will mention some of the unusual challenges and opportunities afforded by marine taxa for genetic research in conservation. Marine organisms often are less accessible for behavioral and natural history observation than are their terrestrial counterparts. Many marine organisms have exceptional dispersal and migratory capabilities. Species' ranges can be vast. Life histories may include high fecundities and explosive reproductive potentials. Many marine species of conservation concern are harvested commercially or illegally and thus economic, social, jurisdictional, and forensic matters often arise in population management, in addition to biological considerations. For a diversity of marine taxa, molecular markers have uncovered previously unknown aspects of behavior, natural history, and population demography that can inform conservation and management decisions. The studies compiled in this volume highlight the scope and imaginative uses of genetic information for conservation challenges in the marine realm

Twenty-five key evolutionary insights from the phylogeographic revolution in population genetics

An overview is provided of 25 novel perspectives that the field of phylogeography has brought to scientific studies of population genetics and speciation. A unifying theme is that microevolu-tion can be described as an extended genealogical process played out in space and time, and reflecting the oft-idiosyncratic biological and environmental factors that have impinged on historical population demography. Most of the empirical and conceptual methods of phylogeo-graphy depart considerably from conventional equilibrium approaches, and they are helping to reorient and extend traditional population genetics in realistic directions that emphasize historical demography and genealogy

Clones, hermaphrodites and pregnancies: Nature's oddities offer evolutionary lessons on reproduction

I love the term 'natural history' because it encapsulates the sentiment that nature's operations have evolutionary etiologies. Charles Darwin was a natural historian par excellence and his elucidation of natural selection, artificial selection, and sexual selection fundamentally changed how scientists interpret the origins of biological features previously ascribed to sentient craftsmanship by supernatural agents. Darwin's insights on evolutionary forces grew from his exceptional knowledge of natural history, yet two key topics steeped in natural history - sex and reproductive genetics - remained poorly understood (and probably even shunned) in Darwin's Victorian era. That situation changed dramatically in the latter half of the 20th century with societal awakenings about sexuality that also happened to coincide with the introduction of molecular parentage analyses that unveiled a plethora of formerly hidden 'sexcapades' throughout the biological world. Here I summarize some of the evolutionary revelations that have emerged from selection theory as applied to genetic and phylogenetic information on clonality, hermaphroditism, and pregnancy, three procreative phenomena that are relatively rare in vertebrate animals and thus offer alternative evolutionary perspectives on standard reproductive modes. Collectively, these three peculiarities of nature illustrate how the abnormal in biology can enlighten evolutionary thought about the norm. © 2011 The Zoological Society of London

The best and the worst of times for evolutionary biology

The 21st century will offer great opportunities, but also challenges, for the field of evolutionary biology, particularly in areas related to molecular genetic technologies, the environment, biodiversity, and public education. The coming decades promise to be both the best and the worst of times for the evolutionary disciplines