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July 1987 - present
June 1981 - June 1987
October 1979 - May 1981
Publications
Publications (320)
Dissecting the molecular basis of adaptation remains elusive despite our ability to sequence genomes and transcriptomes. At present, most genomic research on selection focusses on signatures of selective sweeps in patterns of heterozygosity. Other research has studied changes in patterns of gene expression in evolving populations but has not usuall...
Drosophila experimental evolution, with its well-defined selection protocols, has long supplied useful genetic material for the analysis of functional physiology. While there is a long tradition of interpreting the effects of large-effect mutants physiologically, identifying and interpreting gene-to-phenotype relationships has been challenging in t...
Drosophila experimental evolution, with its well-defined selection protocols, has long supplied useful genetic material for the analysis of functional physiology. While there is a long tradition of interpreting the effects of large-effect mutants physiologically, in the genomic era identifying and interpreting gene-to-phenotype relationships has be...
The molecular basis of adaptation remains elusive even with the current ease of sequencing the genome and transcriptome. We used experimentally evolved populations of Drosophila in conjunction with statistical learning tools to explore interactions between the genome, the transcriptome, and phenotypes. Our results indicate that transcriptomic measu...
Our intuitive understanding of adaptation by natural selection is dominated by the power of selection at early ages in large populations. Yet, as the forces of natural selection fall with adult age, we expect adaptation to be attenuated with age. Explicit simulations of age-dependent adaptation suggest that populations adapt to a novel environment...
Most people are interested in achieving or sustaining health. Unfortunately, there are few topics that have been more subject to confusion and contradiction than that of human health. We believe that an evolutionary perspective can make a signal contribution to clarifying the foundations of health, including the prospects for its successful mainten...
The genomic basis of ageing still remains unknown despite being a topic of study for many years. Here, we present data from 20 experimentally evolved laboratory populations of Drosophila melanogaster that have undergone two different life-history selection regimes. One set of ten populations demonstrates early ageing whereas the other set of ten po...
In experimental evolution, we impose functional demands on laboratory populations of model organisms using selection. After enough generations of such selection, the resulting populations constitute excellent material for physiological research. An intense selection regime for increased starvation resistance was imposed on ten, large, outbred Droso...
Evolutionary convergence is a core issue in the study of adaptive evolution, as well as a highly debated topic at present. Few studies have analyzed this issue using a “real‐time” or evolutionary trajectory approach. Do populations that are initially differentiated converge to a similar adaptive state when experiencing a common novel environment? D...
Evolutionary convergence is a core issue in the study of adaptive evolution, as well as a highly debated topic at present. Few studies have analyzed this issue using a real-time or evolutionary trajectory approach. Do populations initially differentiated converge to a similar adaptive state when experiencing a common novel environment? Drosophila s...
Background
Studies combining experimental evolution and next-generation sequencing have found that adaptation in sexually reproducing populations is primarily fueled by standing genetic variation. Consequently, the response to selection is rapid and highly repeatable across replicate populations. Some studies suggest that the response to selection...
Model organisms subjected to sustained experimental evolution often show levels of phenotypic differentiation that dramatically exceed the phenotypic differences observed in natural populations. Genome-wide sequencing of pooled populations then offers the opportunity to make inferences about the genes that are the cause of these phenotypic differen...
The relative impact of selection, chance and history will determine the predictability of evolution. There is a lack of empirical research on this subject, particularly in sexual organisms. Here we use experimental evolution to test the predictability of evolution. We analyse the real-Time evolution of Drosophila subobscura populations derived from...
We have been developing an approach to the study of life history based chiefly on evolutionary theories that depend on Hamilton's forces of natural selection. After almost forty years of work in this area, we realised that we have been assembling the pieces of an overarching research programme for demography that is distinctively Hamiltonian. Here...
What are the genomic foundations of adaptation in sexual populations? We address this question using fitness-character and whole-genome sequence data from 30 Drosophila laboratory populations. These 30 populations are part of a nearly forty-year laboratory radiation featuring three selection regimes, each shared by ten populations for up to 837 gen...
Medicine has undergone three major revolutions up to the end of the 20th century. Here we propose the need for a fourth: one based on evolutionary biology and genomics. Medicine is reaching the limits of what can be achieved, with its present focus on etiologies of chronic disease that arise from single genetic mutations or the interruption of sing...
Experimental evolutionary genomics now allows biologists to test fundamental theories concerning the genetic basis of adaptation. We have conducted one of the longest laboratory evolution experiments with any sexually-reproducing metazoan, Drosophila melanogaster. We used next-generation resequencing data from this experiment to examine genome-wide...
Drosophila melanogaster is a good model species for the study of heart function. However, most previous work on D. melanogaster heart function has focused on the effects of large-effect genetic variants. We compare heart function among 18 D. melanogaster populations that have been selected for altered development time, aging, or stress resistance....
Drosophila research has identified a new feature of aging that has been called the death spiral. The death spiral is a period prior to death during which there is a decline in life-history characters, such as fecundity, as well as physiological characters. First, we review the data from the Drosophila and medfly literature that suggest the existenc...
In outbred sexually reproducing populations, age-specific mortality rates reach a plateau in late life following the exponential increase in mortality rates that marks aging. Little is known about what happens to physiology when cohorts transition from aging to late life. We measured age-specific values for starvation resistance, desiccation resist...
Laboratory selection experiments are alluring in their simplicity, power, and ability to inform us about how evolution works. A longstanding challenge facing evolution experiments with metazoans is that significant generational turnover takes a long time. In this work, we present data from a unique system of experimentally evolved laboratory popula...
There is considerable evidence for an adaptive role of inversions, but how their genetic content evolves and affects the subsequent evolution of chromosomal polymorphism remains controversial. Here we track how life-history traits, chromosomal arrangements, and 22 microsatellites, within and outside inversions, change in three replicated population...
The biotechnological task of controlling human aging will evidently be complex, given the failure of all simple strategies for accomplishing this task to date. In view of this complexity, a multi-step approach will be necessary. One precedent for a multi-step biotechnological success is the burgeoning control of human infectious diseases from 1840...
The search for compounds that enhance health span has been daunting. Many gerontological experiments on model organisms, including Drosophila species, have examined the effects of individual substances on life span solely. But it is now clear that effective alleviation of aging requires more than merely prolonged survival regardless of other functi...
Unnatural Selection is a well-written book in the tradition of Rachel Carson's Silent Spring. It usefully updates that epochal work, engagingly presenting new research on the impact of chemical products from herbicides to antibiotics, both on other species and on ourselves. Despite its elegant brevity, it covers a satisfying breadth of ecological a...
There is not one systems biology of aging, but two. Though aging can evolve in either sexual or asexual species when there is asymmetric reproduction, the evolutionary genetics of aging in species with frequent sexual recombination are quite different from those arising when sex is rare or absent. When recombination is rare, selection is expected t...
While solutions to major scientific and medical problems are never perfect or complete, it is still reasonable to delineate cases where both have been essentially solved. For example, Darwin's theory of natural selection provides a successful solution to the problem of biological adaptation, while the germ theory of infection solved the scientific...
The roles of history, chance and selection have long been debated in evolutionary biology. Though uniform selection is expected to lead to convergent evolution between populations, contrasting histories and chance events might prevent them from attaining the same adaptive state, rendering evolution somewhat unpredictable. The predictability of evol...
Adaptation is a term that refers to both (i) attributes that enhance Darwinian fitness and (ii) evolutionary processes that produce such attributes, such as natural selection. It is inherently difficult to establish that a character is an adaptation. It is also difficult to study natural selection. Scientific opinion has swung between extreme views...
Census population size, sex-ratio and female reproductive success were monitored in 10 laboratory populations of Drosophila melanogaster selected for different ages of reproduction. With this demographic information, we estimated eigenvalue, variance and probability of allele loss effective population sizes. We conclude that estimates of effective...
Human genome-wide association studies (GWAS) of longevity attempt to identify alleles at different frequencies in the extremely
old, relative to a younger control sample. Here, we apply a GWAS approach to “synthetic” populations of Drosophila melanogaster derived from a small number of inbred founders. We used next-generation DNA sequencing to esti...
Founder effects during colonization of a novel environment are expected to change the genetic composition of populations, leading to differentiation between the colonizer population and its source population. Another expected outcome is differentiation among populations derived from repeated independent colonizations starting from the same source....
While working on a draft of a manuscript for his research on the scientific problem of biological immortality the author stumbled upon a penicillin-like idea that gave him a different view of the prospects for significantly slowing human aging, and indeed the prospects for starting to move toward biological immortality for a significant number of p...
We have investigated the effects of brief, non-specific deuteration of Drosophila melanogaster by including varying percentages of 2H (D) in the H2O used in the food mix consumed during initial development. Up to 22.5% D2O in H2O was administered, with the result that a low percentage of D2O in the water increased mean lifespan, while the highest p...
Most founding events entail a reduction in population size, which in turn leads to genetic drift effects that can deplete alleles. Besides reducing neutral genetic variability, founder effects can in principle shift additive genetic variance for phenotypes that underlie fitness. This could then lead to different rates of adaptation among population...
In a variety of organisms, adulthood is divided into aging and late life, where aging is a period of exponentially increasing mortality rates and late life is a period of roughly plateaued mortality rates. In this study we used ∼57,600 Drosophila melanogaster from six replicate populations to examine the physiological transitions from aging to late...
Hang on long enough and your body will stop ageing. We don't know why but that shouldn't stop us exploiting it
For more than 40 years, multiple laboratories have studied Drosophila stocks that have been forced to evolve slowed rates of aging and increased average longevities. These stocks have been used to test both physiological and genetic theories of aging, yielding a number of interesting findings. A little-noticed problem is that these tests have too f...
There used to be a broad split within the experimental genetics research community between those who did mechanistic research using homozygous laboratory strains and those who studied patterns of genetic variation in wild populations. The former benefited from the advantage of reproducible experiments, but faced difficulties of interpretation given...
Five laboratory populations of Drosophila melanogaster which exhibit postponed senescence were compared with five control populations. Comparisons were made with respect to weights of whole bodies, body parts, and water content. Ovaries of young adults from populations exhibiting postponed senescence were approximately half the weight of ovaries of...
Senescence, the endogenous deterioration of health at later ages, can be explained in terms of evolution. Senescence is not due to group selection but to the decline with age in the force of natural selection acting on individuals. This decline allows the spread of alleles with deleterious effects on late health. Such alleles do not appear to have...
Experimental evolution systems allow the genomic study of adaptation, and so far this has been done primarily in asexual systems with small genomes, such as bacteria and yeast. Here we present whole-genome resequencing data from Drosophila melanogaster populations that have experienced over 600 generations of laboratory selection for accelerated de...
In contrast to the common view that aging is due to accumulated damage or disorder, we have demonstrated that natural selection
can readily extend lifespan by selecting many small-effect changes in gene expression. Using wild type Drosophila as a model
system, we were able to select such small-effect genetic variants over a 27 year period resulting...
Experimental approaches to evolution provide indisputable evidence of evolution by directly observing the process at work. Experimental evolution deliberately duplicates evolutionary processes-forcing life histories to evolve, producing adaptations to stressful environmental conditions, and generating lineage splitting to create incipient species....
The Gods ProblemThe Evolution of Free Will Is Our Starting PointSo Gods EvolvedGods Are Hidden Inside UsThe Godless Must Walk the EarthGods Must Be Made ManifestReligion Mediates Between Free Will and GodsLiving in Harmony With Our Actual Gods
ABSTRACT: Here we present a correction to our article "Evolutionary dynamics of molecular markers during local adaptation: a case study in Drosophila subobscura". We have recently detected an error concerning the application of the Ln RH formula - a test to detect positive selection - to our microsatellite data. Here we provide the corrected data a...
Aging is not simply an accumulation of damage or inappropriate higher-order signaling, though it does secondarily involve both of these subsidiary mechanisms. Rather, aging occurs because of the extensive absence of adaptive genomic information required for survival to, and function at, later adult ages, due to the declining forces of natural selec...
Experimental evolution is a powerful approach that can be used for the study of adaptation. Evolutionary biologists often use Drosophila as a model organism in experiments that test theories about the evolution of traits related to fitness. Such evolution experiments can take three forms: direct selection for a trait of interest; surveys of traits...
Aging, like all biological characters, evolves. From an evolutionary point of view, it can be defined as a sustained age-specific decline of fitness-related characteristics that is not due to external environmental factors. This chapter discusses the evolutionary theories of aging and the experimental studies that have tested and challenged them, a...
Darwin's erroneous reasoning concerning heredity was influenced by his gradualist prejudices. This style of thinking prevented Darwin from giving appropriate attention to the hypothesis of discrete inheritance, leading evolutionary biology up a blind alley of blending inheritance. Darwin's other mistake also came from his gradualist preconceptions....
Human mortality data show stabilization in mortality rates at very late ages. But human mortality data are difficult to interpret because they are affected by changing medical practices and other historically variable causes of death. However, in the 1990s, data from a variety of labs showed that the mortality rates of medflies, fruit flies, wasps,...
Evolution depends on genetic variation generated by mutation or recombination from standing genetic variation. In sexual organisms, little is known about the molecular population genetics of adaptation and reverse evolution. We carry out 50 generations of experimental reverse evolution in populations of Drosophila melanogaster, previously different...
Small invertebrate animals, such as nematodes and fruit flies, are increasingly being used to test candidate drugs both for specific therapeutic purposes and for long-term health effects. Some of the protocols used in these experiments feature such experimental design features as lifelong virginity and very low densities. By contrast, the ability o...
