The Anomaly of Bacterial Genetics

2021 ◽  
pp. 37-43
Author(s):  
Thomas E. Schindler
Keyword(s):  
Molecular Biology ◽  
Model Systems ◽  
Darwinian Evolution ◽  
Bacterial Conjugation ◽  
Bacterial Genetics ◽  
New Model ◽  
Novel Approach ◽  
Foundational Research ◽  
Gregor Mendel ◽  
Classical Genetics

This chapter reviews the research that set the stage for Joshua Lederberg’s surprising discovery of bacterial conjugation. While the foundational research of Gregor Mendel and his principles of inheritance had been effectively combined with Darwinian evolution, producing the Modern Synthesis in the mid-forties, bacteria did not fit into this grand synthesis. Most biologists believed that bacteria were too primitive to have real genes. But Delbruck, Hershey and Luria organized the Phage School, leading a novel approach to discovering the molecular biology of the gene by studying bacteriophages. Microbiologists like Tracy Sonneborn and Carl Lindegren turned to alternative microorganisms—protists, fungi, and yeast—to develop new model systems that offered advantages over the classical genetics organisms of animals and plants. The research of Edward Tatum and Jacques Monod indicated that mutations seemed to explain variation in bacteria. For many years, however, bacteriologists had known that bacteria reproduced by fission. The lack of any genetic hybridization seemed to argue against using bacteria to study basic genetic processes.

scholarly journals Overview of Arabidopsis as a Genetics Model System and Its Limitation, Leading to the Development of Emerging Plant Model Systems

2021 ◽  
Author(s):  
Madhabendra Mohon Kar ◽  
Ayan Raichaudhuri
Keyword(s):  
Molecular Biology ◽  
Genetic Basis ◽  
Model System ◽  
Model Systems ◽  
Plant Model ◽  
New Model ◽  
Plant System ◽  
Model Plant ◽  
System A ◽  
Plant Process

Model plant systems make it easier to perform experiments with them. They help to understand and expand our knowledge about the genetic basis behind different plant process. Also, it is easier to design and perform genetic and genomic experiments using a model plant system. A. thaliana was initially chosen as the model plant system, and remains to this date, one of the most widely studied plant. With the advent of better molecular biology and sequencing tools and to understand the genetic basis for the unique processes in different plant species, there is emergence of several new model systems.

Tailoring Polymer Surfaces for Controlled Cell Behavior

1998 ◽  
Vol 530 ◽  
Author(s):  
A.M. Mayes ◽  
D.J. Irvine ◽  
L.G. Griffith
Keyword(s):  
Protein Adsorption ◽  
Surface Segregation ◽  
Cell Attachment ◽  
Model Systems ◽  
Protein Resistance ◽  
Small Proteins ◽  
Novel Approach ◽  
Poly Ethylene ◽  
Comb Copolymer ◽  
Adhesion Ligand

AbstractAn ideal surface for many biomaterials applications would resist nonspecific protein adsorption while at the same time providing a means for specifically signaling cells to guide survival, growth, migration, and differentiation. This work was directed towards the investigation of model systems and clinically-applicable materials which provide both of these surface requirements. Model systems were prepared by chemically grafting end-functionalized star poly(ethylene oxide) (PEO) to surfaces. The end-grafted polymers provide a means for cell-signaling through coupling of peptides to the free chain ends. Protein adsorption on star vs. linear grafted layers was compared. To further understand these results, neutron reflectivity studies were carried out in situ for solvated PEO surfaces to determine the concentration profiles of the swollen grafted layers. Surprisingly, grafted PEO layers which resist protein adsorption have low concentrations of polymer segments throughout the swollen layer. We find that dense star architectures which might be expected to impart improved protein resistance in fact allow small proteins to adsorb. For clinical materials, a novel approach to the surface modification of poly(lactide) (PLA) has been taken by surface segregating a comb copolymer containing a PLA backbone and poly(ethylene glycol) teeth. The ends of the teeth provide sites for surface tethering of peptide ligands. Comb surfaces without tethered ligands are cell adhesion resistant, indicating strong protein adsorption resistance. By then incorporating an adhesion ligand, modulation of cell morphology on comb surfaces has been demonstrated. Finally, the surface segregation of the comb to the surface of PLA was shown via cell attachment assays and XPS measurements.

COMPARING VIRUS CLASSIFICATION USING GENOMIC MATERIALS ACCORDING TO DIFFERENT TAXONOMIC LEVELS

2013 ◽  
Vol 11 (06) ◽  
pp. 1343003 ◽  
Author(s):  
JING-DOO WANG
Keyword(s):  
Molecular Biology ◽  
Dna Sequences ◽  
Protein Sequences ◽  
Experimental Results ◽  
Virus Classification ◽  
Taxonomic Level ◽  
Biological Classification ◽  
Novel Approach

In this paper, three genomic materials — DNA sequences, protein sequences, and regions (domains) are used to compare methods of virus classification. Virus classes (categories) are divided by various taxonomic level of virus into three datasets for 6 order, 42 family, and 33 genera. To increase the robustness and comparability of experimental results of virus classification, the classes are selected that contain at least 10 instances, and meanwhile each instance contains at least one region name. Experimental results show that the approach using region names achieved the best accuracies — reaching 99.9%, 97.3%, and 99.0% for 6 orders, 42 families, and 33 genera, respectively. This paper not only involves exhaustive experiments that compare virus classifications using different genomic materials, but also proposes a novel approach to biological classification based on molecular biology instead of traditional morphology.

Gregor Mendel, Thomas Hunt Morgan en experimenten in de klassieke genetica

2021 ◽  
Vol 113 (1) ◽  
pp. 107-135
Author(s):  
Bert Leuridan
Keyword(s):  
Causal Discovery ◽  
Evidential Value ◽  
Crucial Feature ◽  
Manipulative Experiments ◽  
Scientific Approach ◽  
Gregor Mendel ◽  
Classical Genetics ◽  
Thomas Hunt Morgan

Abstract Gregor Mendel, Thomas Hunt Morgan and experiments in classical geneticsIn the middle of the 19th century, Gregor Mendel performed a series of crosses with pea plants to investigate how hybrids are formed. Decades later, Thomas Hunt Morgan finalized the theory of classical genetics. An important aspect of Mendel’s and Morgan’s scientific approach is that they worked in a systematic, experimental fashion. But how did these experiments proceed? What is the relation between these experiments and Mendel’s and Morgan’s explanatory theories? What was their evidential value? Using present-day insights in the nature of experimentation I will show that the answer to these questions is fascinating but not obvious. Crossings in classical genetics lacked a crucial feature of traditional experiments for causal discovery: manipulation of the purported causes. Hence they were not traditional, ‘manipulative’ experiments, but ‘selective experiments’.

6. Genes

2019 ◽  
pp. 83-100
Author(s):  
Samir Okasha
Keyword(s):  
Molecular Genetics ◽  
Precise Definition ◽  
History Of Genetics ◽  
History Of ◽  
Gregor Mendel ◽  
The 1950S ◽  
Classical Genetics

There is no satisfactory one-line answer to the question ‘what exactly is a gene?’. The reasons why a precise definition is elusive are particularly interesting, and raise a number of philosophical subtleties. ‘Genes’ delves briefly into the history of genetics in order to understand them. It first looks at the work of Gregor Mendel in the 1860s and then the era of classical genetics in the 1920s and 1930s. It then moves on to molecular genetics, which came to fruition in the 1950s. How does the gene of Mendelian or classical genetics relate to the gene of molecular genetics? This question has long occupied philosophers of biology.

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