Molecular Basis Of Evolution Research Articles

The Molecular Basis of Evolution and Disease: A Cold War Alliance

This paper extends previous arguments against the assumption that the study of variation at the molecular level was instigated with a view to solving an internal conflict between the balance and classical schools of population genetics. It does so by focusing on the intersection of basic research in protein chemistry and the molecular approach to disease with the enactment of global health campaigns during the Cold War period. The paper connects advances in research on protein structure and function as reflected in Christian Anfinsen's The molecular basis of evolution, with a political reading of Emilé Zuckerkandl and Linus Pauling's identification of molecular disease and evolution. Beyond atomic fallout, these advances constituted a rationale for the promotion of genetic surveys of human populations in the Third World, in connection with international health programs. Light is shed not only on the experimental roots of the molecular challenge but on the broader geopolitical context where the rising role of biomedicine and public health (particularly the malaria eradication campaigns) had an impact on evolutionary biology.

Propuesta didáctica de enseñanza con simulaciones para estudiantes del profesorado en Ciencias Biológicas

The aim of this study was to develop a didactic proposal for teaching with simulations (DPTS) and analyze the conditions and didactic moments that accompany its implementation for students of the professorate in Biological Sciences. Thus, it is intended to facilitate the learning of disciplinary content and its didactics, and the acquisition of autonomy in the use of technological resources by future professors. The Forensic EA Lite simulation, a software designed for addressing contents of molecular evolution, was used. Molecular evolution is one of the program units of the subject “Molecular Genetics” in which this proposal was carried out. DPTS was designed, implemented, adjusted through practice and finally resulted in the following didactic moments: presentation, program exploration and appropriation of specific vocabulary, articulation between simulation and disciplinary content, correlation activities, time for metacognition and time for content transfer (enforcement activities). Difficulties and benefits of the proposal for learning the subject, acquisition of autonomy with the technological resource and contributions for teacher training were evaluated. The development and adjustment of the proposal were focused on both didactic decisions made by the teacher to design and put into practice a didactic sequence of the simulation used and on the learning demands of students, in a process of continuous feedback. The proposal facilitated learning of the molecular basis of evolution, made the students exercise autonomy when using technological resources, and provided a form of didactic intervention to teach with simulations in theoretical constructivist frameworks for the practice teachers in training in biology.

Laboratory Activities to Support Student Understanding of the Molecular Mechanisms of Mutation & Natural Selection

The molecular basis of evolution is an important and challenging concept for students to understand. In a previous article, we provided some of the scientific background necessary to teach this topic. This article features a series of laboratory activities demonstrating that molecular events can alter the genomes of organisms. These activities are most appropriate for undergraduate students in Honors Biology, Genetics, or Molecular Biology courses. Student laboratory instructions are included to allow students to conduct the activities, make observations, interpret the results, and draw conclusions.

Instant Update

The molecular basis of evolution is an important concept to understand but one that students and teachers often find challenging. This article provides training and guidance for teachers on how to present molecular evolution concepts so that students will associate molecular changes with the evolution of form and function in organisms. Included are examples that illustrate how mutation followed by selection causes populations to evolve. Next month we will share lab activities that illustrate the concepts and reinforce the complementary roles of mutation and selection in the overall process of evolution.

Comparative Gene Expression Analysis Among Vocal Learners (Bengalese Finch and Budgerigar) and Non-Learners (Quail and Ring Dove) Reveals Variable Cadherin Expressions in the Vocal System

Birds use various vocalizations to communicate with one another, and some are acquired through learning. So far, three families of birds (songbirds, parrots, and hummingbirds) have been identified as having vocal learning ability. Previously, we found that cadherins, a large family of cell-adhesion molecules, show vocal control-area-related expression in a songbird, the Bengalese finch. To investigate the molecular basis of evolution in avian species, we conducted comparative analysis of cadherin expressions in the vocal and other neural systems among vocal learners (Bengalese finch and budgerigar) and a non-learner (quail and ring dove). The gene expression analysis revealed that cadherin expressions were more variable in vocal and auditory areas compared to vocally unrelated areas such as the visual areas among these species. Thus, it appears that such diverse cadherin expressions might have been related to generating species diversity in vocal behavior during the evolution of avian vocal learning.

Origin and Phylogenetic Distribution of Alu DNA Repeats: Irreversible Events in the Evolution of Primates

Over the past 60 million years, or so, approximately one million copies of Alu DNA repeats have accumulated in the genome of primates, in what appears to be an ongoing process. We determined the phylogenetic distribution of specific Alu (and other) DNA repeats in the genome of several primates: human, chimpanzee, gorilla, orangutan, baboon, rhesus, and macaque. At the population level studied, the majority of the repeats was found to be fixed in the primate species. Our data suggest that new Alu elements arise in unique, irreversible events, in a mechanism that seems to preclude precise excision and loss. The same insertions did not arise independently in two species. Once inserted and genetically fixed, the DNA elements are retained in all descendant lineages. The irreversible expansion of Alu s introduces a vector of time into the evolutionary process, and provides realistic (rather than statistical) answers to questions on phylogenies. In contrast to point mutations, the present distribution of individual Alu s is congruent with just one phylogeny. We submit that only irreversible and taxonomically relevant events are at the molecular basis of evolution. Most point mutations do not belong to this category.

Retroviruses and Oncogenes II (Nobel Lecture)

The suggestion that genetic changes might be responsible for cancer was long controversial. The joint results of Harold E. Varmus and J. Michael Bishop, obtained over many years, lent much support to this idea and led to the award of the Nobel Prize in medicine and physiology in 1989. Their interest in oncogenes and retroviruses opened up some of the most interesting areas in modern biology: the genetic basis of cancer, the transposition of DNA through RNA intermediates, the control of gene expression in eukaryotes, and the molecular basis of evolution. Their work takes on additional importance in light of the worldwide spread of a human retrovirus, HIV, which causes AIDS. The two articles give an overview of the history of research in this area and lead the reader to topics of current interest.

Retroviruses and Oncogenes I (Nobel Lecture)

The suggestion that genetic changes might be responsible for cancer was long controversial. The joint results of Harold E. Varmus and J. Michael Bishop, obtained over many years, lent much support to this idea and led to the award of the Nobel Prize in medicine and physiology in 1989. Their interest in oncogenes and retroviruses opened up some of the most interesting areas in modern biology: the genetic basis of cancer, the transposition of DNA through RNA intermediates, the control of gene expression in eukaryotes, and the molecular basis of evolution. Their work takes on additional importance in light of the worldwide spread of a human retrovirus, HIV, which causes AIDS. The two articles give an overview of the history of research in this area and lead the reader to topics of current interest.

Molecular mechanisms in genetic stability and change: the role of deoxyribonucleotide pool balance.

For both theoretical and practical reasons, elucidation of the dialectical processes of genetic stability and change is one of the central problems of biology. The molecular basis of evolution resides in the intimately associated mechanisms of heredity and mutagenesis, which together have led gradually to the accumulation of a vast store of genetic variation within gene pools. Although the actual course of evolution is mediated by natural selection, in the absence of variation, selection can do nothing [7]. Heredity is a manifestation of the stability of genes from one generation to the next. It is necessary for the formation of normal progeny, and for the integrity and longevity of species. Genetic variation is a manifestation of the instability of genes, and of the ‘fluidity’ of the genome. It is responsible, ultimately, for the origin of species, but more immediately, for a substantial number of serious human diseases, including cancer.

Induction of Resistance or Susceptibility

Unlike animals, plants have no antibody-mediated resistance mechanisms. During their evolution, however, plants acquired not only the ability to adapt to hostile environments, but also versatile defense mechanisms against enemies. Pathogens, On the other hand, have evolved to overcome the physical and chemical barriers the plants invented for their survival, thus impelling coevolu­ tion. Whatever the molecular basis of evolution may have been, parasites and hosts coevolved for their mutual survival. The basic principles of parasitism have been discussed mainly in terms of the resistance mechanisms plants use in response to invading microbes. Resistance mechanisms are important in many respects. They attract biochemists who seek to elucidate the molecular basis of resistance and suggest possible applications to disease control. In fact, extensive studies on resistance mechanisms pursued for the last two decades disclosed various physical and chemical barriers that plants utilize to protect themselves from invaders, such as papillae, lignifica­ tion of walls, preformed compounds, phytoalexins, and so on. In spite of this progress in the study of resistance, little is known about the mechanisms of plant susceptibility to pathogens, although the function of host-specific toxins has been studied in this respect. In this review, I wish to discuss some facets of host-pathogen interactions from a viewpoint slightly different from those emphasized in most of the literature. It is certainly difficult to extend ideas on induced resistance or susceptibility in the presence of many excellent books and reviews on this subject, especially the two volumes of Plant Disease. edited by Horsfall & Cowling (49,50), and Active Defense Mechanisms in Plants. edited by Wood (100). Following the recommendation of the editor, I emphasize concepts rather than a survey of the literature.

Metabolism of Long-Chain Fatty Acids in the Rumen

Publisher Summary This chapter discusses the metabolism of long-chain fatty acids in the rumen. The studies described in the chapter reveal the importance of veterinary problems in stimulating new interest in biochemical processes that might improve foods of animal origin and, thus, human nutrition. They have contributed to one of the most interesting areas of biochemical studies: the molecular basis of evolution. They have allowed the discovery of living biochemical fossils and have helped to elucidate the mechanisms of branched fatty acid biosynthesis and unsaturated fatty acid biohydrogenation. Studies on the origin of petroleum in association with studies on biological evolution show that branched-chain hydrocarbon structures derive from the corresponding fatty acid molecules. In fatty acid biohydrogenation, the enzyme responsible for the disappearance of a π bond probably represents a vestige, whose deep biological meaning is now hidden in the rumen, of the mechanisms of energy transformations of primitive organisms, when there was no oxygen in the atmosphere, at the beginning of life on earth.