scholarly journals Isoenzimas

2017 ◽  
pp. 77
Author(s):  
Nidia Pérez-Nasser ◽  
Daniel Piñero
Keyword(s):  
Population Genetics ◽  
Life History ◽  
Molecular Markers ◽  
Natural Selection ◽  
Evolutionary Biology ◽  
Mating Systems ◽  
Wild Relatives ◽  
Cultivated Plants ◽  
Origin And Evolution ◽  
Evolutionary Studies

This work presents a review of the use of enzymes as molecular markers for evolutionary studies, in particular population genetics. First, the methodology of starch electrophoresis is shown as a useful tool To detect variation within and among populations. Second, applications to evolutionary biology are presented. In plants these markers have been used for 1] to study mating systems, 2] do phylogenetics and taxonomy, 3] study natural selection components, 4] to correlate genetics and life history characters and 5] understand the origin and evolution of cultivated plants and their wild relatives

scholarly journals Genome size correlates with reproductive fitness in seed beetles

2015 ◽  
Vol 282 (1815) ◽  
pp. 20151421 ◽  
Author(s):  
Göran Arnqvist ◽  
Ahmed Sayadi ◽  
Elina Immonen ◽  
Cosima Hotzy ◽  
Daniel Rankin ◽  
...  
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Genome Size ◽  
Evolutionary Biology ◽  
Large Scale ◽  
Life History Traits ◽  
Single Species ◽  
Reproductive Fitness ◽  
Correlated Evolution ◽  
Seed Beetles

The ultimate cause of genome size (GS) evolution in eukaryotes remains a major and unresolved puzzle in evolutionary biology. Large-scale comparative studies have failed to find consistent correlations between GS and organismal properties, resulting in the ‘ C -value paradox’. Current hypotheses for the evolution of GS are based either on the balance between mutational events and drift or on natural selection acting upon standing genetic variation in GS. It is, however, currently very difficult to evaluate the role of selection because within-species studies that relate variation in life-history traits to variation in GS are very rare. Here, we report phylogenetic comparative analyses of GS evolution in seed beetles at two distinct taxonomic scales, which combines replicated estimation of GS with experimental assays of life-history traits and reproductive fitness. GS showed rapid and bidirectional evolution across species, but did not show correlated evolution with any of several indices of the relative importance of genetic drift. Within a single species, GS varied by 4–5% across populations and showed positive correlated evolution with independent estimates of male and female reproductive fitness. Collectively, the phylogenetic pattern of GS diversification across and within species in conjunction with the pattern of correlated evolution between GS and fitness provide novel support for the tenet that natural selection plays a key role in shaping GS evolution.

Evolution: Medicine’s most basic science

2020 ◽  
pp. 39-42
Author(s):  
Randolph M. Nesse ◽  
Richard Dawkins
Keyword(s):  
Population Genetics ◽  
Natural Selection ◽  
Basic Science ◽  
Evolutionary Biology ◽  
Phylogenetic Trees ◽  
The Body ◽  
Clinical Implications ◽  
Trade Offs ◽  
The Cost

The role of evolutionary biology as a basic science for medicine is expanding rapidly. Some evolutionary methods are already widely applied in medicine, such as population genetics and methods for analysing phylogenetic trees. Newer applications come from seeking evolutionary as well as proximate explanations for disease. Traditional medical research is restricted to proximate studies of the body’s mechanism, but separate evolutionary explanations are needed for why natural selection has left many aspects of the body vulnerable to disease. There are six main possibilities: mismatch, infection, constraints, trade-offs, reproduction at the cost of health, and adaptive defences. Like other basic sciences, evolutionary biology has limited direct clinical implications, but it provides essential research methods, encourages asking new questions that foster a deeper understanding of disease, and provides a framework that organizes the facts of medicine.

Developmental biology and human evolution

2011 ◽  
Vol 1 (1) ◽  
pp. e2
Author(s):  
Jeffrey H. Schwartz
Keyword(s):  
Biological Sciences ◽  
Population Genetics ◽  
Evolutionary Biology ◽  
Molecular Change ◽  
Human Fossil ◽  
Evolutionary Studies ◽  
History Of ◽  
Modern Evolutionary Synthesis ◽  
Organismal Development ◽  
Taxic Diversity

The Evolutionary or Modern Evolutionary Synthesis (here identified as the Synthesis) has been portrayed as providing the foundation for uniting a supposed disarray of biological disciplines through the lens of Darwinism fused with population genetics. Rarely acknowledged is that the Synthesis’s success was also largely due to its architects’ effectiveness in submerging British and German attempts at a synthesis by uniting the biological sciences through shared evolutionary concerns. Dobzhansky and Mayr imposed their bias toward population genetics, population (as supposedly opposed to typological) thinking, and Morgan’s conception of specific genes for specific features (here abbreviated as genes for) on human evolutionary studies. Dobzhansky declared that culture buffered humans from the whims of selection. Mayr argued that as variable as humans are now, their extinct relatives were even more variable; thus the human fossil did not present taxic diversity and all known fossils could be assembled into a gradually changing lineage of time-successive species. When Washburn centralized these biases in the new physical anthropology the fate of paleoanthropology as a non-contributor to evolutionary theory was sealed. Molecular anthropology followed suit in embracing Zuckerkandl and Pauling’s assumption that molecular change was gradual and perhaps more importantly continual. Lost in translation was and still is an appreciation of organismal development. Here I will summarize the history of these ideas and their alternatives in order to demonstrate assumptions that still need to be addressed before human evolutionary studies can more fully participate in what is a paradigm shift-in-the-making in evolutionary biology.

Evolution of senescence: late survival sacrificed for reproduction

1991 ◽  
Vol 332 (1262) ◽  
pp. 15-24 ◽  
Keyword(s):  
Population Genetics ◽  
Life History ◽  
Natural Selection ◽  
Antagonistic Pleiotropy ◽  
Widespread Occurrence ◽  
Disposable Soma Theory ◽  
Somatic Tissues ◽  
Competing Demands ◽  
Early Effects ◽  
Late Survival

In so far as it is associated with declining fertility and increasing mortality, senescence is directly detrimental to reproductive success. Natural selection should therefore act in the direction of postponing or eliminating senescence from the life history. The widespread occurrence of senescence is explained by observing that (i) the force of natural selection is generally weaker at late ages than at early ages, and (ii) the acquisition of greater longevity usually involves some cost. Two convergent theories are the ‘antagonistic pleiotropy’ theory, based in population genetics, and the ‘disposable soma’ theory, based in physiological ecology. The antagonistic pleiotropy theory proposes that certain alleles that are favoured because of beneficial early effects also have deleterious later effects. The disposable soma theory suggests that because of the competing demands of reproduction less effort is invested in the maintenance of somatic tissues than is necessary for indefinite survival.

Power and Evolutionary Fitness of Teleosts

1982 ◽  
Vol 39 (1) ◽  
pp. 3-13 ◽  
Author(s):  
D. M. Ware
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Optimal Foraging ◽  
Evolutionary Biology ◽  
Life History Theory ◽  
A Priori ◽  
Empirical Work ◽  
Physiological Basis ◽  
Vital Functions ◽  
Surplus Power

The use of optimization arguments in evolutionary biology has been criticized because the methodology requires an assumption about what is being maximized by natural selection. As optimality arguments are often a priori and always speculative, the critics point out that there is no theoretical basis for any maximization principles in biology. They contend that only empirical work can establish if there are some properties of species that are generally maximized by natural selection. I accept this standard for evaluation, and argue that the concept of surplus power, which provides a physiological basis for optimal foraging and life history theory, is related to fitness. Evidence in the form of specific morphological and behavioral traits in teleost fishes is presented to demonstrate that natural selection has increased surplus power. Life history theory is concerned with how power is allocated by organisms to various vital functions; therefore, the specific problem of stock and recruitment in fisheries can be treated as a special application of life history theory. Some implications about the dynamics and possible survival value of different reproductive strategies exhibited by teleosts are discussed.Key words: surplus power, evolutionary biology, optimal foraging, life history theory, fitness

scholarly journals What have humans done for evolutionary biology? Contributions from genes to populations

2017 ◽  
Vol 284 (1866) ◽  
pp. 20171164 ◽  
Author(s):  
Michael Briga ◽  
Robert M. Griffin ◽  
Vérane Berger ◽  
Jenni E. Pettay ◽  
Virpi Lummaa
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Human Study ◽  
Human Studies ◽  
Human Populations ◽  
Evolutionary Processes ◽  
Biological Relevance ◽  
Evolutionary Studies ◽  
Almost All ◽  
Study Designs

Many fundamental concepts in evolutionary biology were discovered using non-human study systems. Humans are poorly suited to key study designs used to advance this field, and are subject to cultural, technological, and medical influences often considered to restrict the pertinence of human studies to other species and general contexts. Whether studies using current and recent human populations provide insights that have broader biological relevance in evolutionary biology is, therefore, frequently questioned. We first surveyed researchers in evolutionary biology and related fields on their opinions regarding whether studies on contemporary humans can advance evolutionary biology. Almost all 442 participants agreed that humans still evolve, but fewer agreed that this occurs through natural selection. Most agreed that human studies made valuable contributions to evolutionary biology, although those less exposed to human studies expressed more negative views. With a series of examples, we discuss strengths and limitations of evolutionary studies on contemporary humans. These show that human studies provide fundamental insights into evolutionary processes, improve understanding of the biology of many other species, and will make valuable contributions to evolutionary biology in the future.

scholarly journals Identification of High Molecular Variation Loci in Complete Chloroplast Genomes of Mammillaria (Cactaceae, Caryophyllales)

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 830
Author(s):  
Delil A. Chincoya ◽  
Alejandro Sanchez-Flores ◽  
Karel Estrada ◽  
Clara E. Díaz-Velásquez ◽  
Antonio González-Rodríguez ◽  
...  
Keyword(s):  
Population Genetics ◽  
Molecular Markers ◽  
Dna Sequences ◽  
Phylogenetic Relationships ◽  
Molecular Variation ◽  
Short Sequence ◽  
Dna Variation ◽  
Chloroplast Genomes ◽  
Evolutionary Studies ◽  
Phylogenetic Resolution

In plants, partial DNA sequences of chloroplasts have been widely used in evolutionary studies. However, the Cactaceae family (1500–1800 species) lacks molecular markers that allow a phylogenetic resolution between species and genera. In order to identify sequences with high variation levels, we compared previously reported complete chloroplast genomes of seven species of Mammillaria. We identified repeated sequences (RSs) and two types of DNA variation: short sequence repeats (SSRs) and divergent homologous loci. The species with the highest number of RSs was M. solisioides (256), whereas M. pectinifera contained the highest amount of SSRs (84). In contrast, M. zephyranthoides contained the lowest number (35) of both RSs and SSRs. In addition, five of the SSRs were found in the seven species, but only three of them showed variation. A total of 180 homologous loci were identified among the seven species. Out of these, 20 loci showed a molecular variation of 5% to 31%, and 12 had a length within the range of 150 to 1000 bp. We conclude that the high levels of variation at the reported loci represent valuable knowledge that may help to resolve phylogenetic relationships and that may potentially be convenient as molecular markers for population genetics and phylogeographic studies.

scholarly journals How can we estimate natural selection on endocrine traits? Lessons from evolutionary biology

2016 ◽  
Vol 283 (1843) ◽  
pp. 20161887 ◽  
Author(s):  
Frances Bonier ◽  
Paul R. Martin
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Recent Work ◽  
Environmental Conditions ◽  
Evolutionary Biology ◽  
Endocrine System ◽  
Adaptive Plasticity ◽  
Evolutionary Perspective ◽  
System Evolution ◽  
Fitness Consequences

An evolutionary perspective can enrich almost any endeavour in biology, providing a deeper understanding of the variation we see in nature. To this end, evolutionary endocrinologists seek to describe the fitness consequences of variation in endocrine traits. Much of the recent work in our field, however, follows a flawed approach to the study of how selection shapes endocrine traits. Briefly, this approach relies on among-individual correlations between endocrine phenotypes (often circulating hormone levels) and fitness metrics to estimate selection on those endocrine traits. Adaptive plasticity in both endocrine and fitness-related traits can drive these correlations, generating patterns that do not accurately reflect natural selection. We illustrate why this approach to studying selection on endocrine traits is problematic, referring to work from evolutionary biologists who, decades ago, described this problem as it relates to a variety of other plastic traits. We extend these arguments to evolutionary endocrinology, where the likelihood that this flaw generates bias in estimates of selection is unusually high due to the exceptional responsiveness of hormones to environmental conditions, and their function to induce adaptive life-history responses to environmental variation. We end with a review of productive approaches for investigating the fitness consequences of variation in endocrine traits that we expect will generate exciting advances in our understanding of endocrine system evolution.

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