Molecular evolution is the process of evolution at the scale of DNA, RNA, and proteins. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl Molecular evolution emerged as a scientific field in the 1960s as researchers from molecular biology, evolutionary biology and population genetics sought to understand recent discoveries on the structure and function of nucleic acids and protein. Molecular biology is the study of Biology at a molecular level Evolutionary biology is a sub-field of Biology concerned with the origin of Species from a Common descent, and Descent of species Population genetics is the study of the Allele frequency distribution and change under the influence of the four evolutionary forces Natural selection, Genetic Some of the key topics that spurred development of the field have been the evolution of enzyme function, the use of nucleic acid divergence as a "molecular clock" to study species divergence, and the origin of non-functional or junk DNA. The molecular clock (based on the molecular clock hypothesis ( MCH) is a technique in Molecular evolution to relate the divergence time of two Species In Molecular biology, junk DNA is a provisional label for the portions of the DNA sequence of a Chromosome or a Genome for which no Recent advances in genomics, including whole-genome sequencing, high-throughput protein characterization, and bioinformatics have led to a dramatic increase in studies on the topic. Bioinformatics is the application of information technology to the field of molecular biology In the 2000s, some of the active topics have been the role of gene duplication in the emergence of novel gene function, the extent of adaptive molecular evolution versus neutral drift, and the identification of molecular changes responsible for various human characteristics especially those pertaining to infection, disease, and cognition. Gene duplication (or chromosomal duplication) is any duplication of a region of DNA that contains a Gene; it may occur as an error in Homologous An infection is the detrimental Colonization of a host Organism by a foreign Species. A disease is an abnormal condition of an organism that impairs bodily functions and can be deadly Cognition is a concept used in different ways by different disciplines but is generally accepted to mean the process of awareness or thought
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Principles of molecular evolution
Mutations
Main article: Mutation
Mutations are permanent, transmissible changes to the genetic material (usually DNA or RNA) of a cell. In biology mutations are changes to the Nucleotide sequence of the Genetic material of an organism Genetic material is used to store the genetic information of an organic life form Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called Mutations can be caused by copying errors in the genetic material during cell division and by exposure to radiation, chemicals, or viruses, or can occur deliberately under cellular control during the processes such as meiosis or hypermutation. Cell division is a process by which a cell, called the parent cell divides into two or more cells called daughter cells. Radiation, as in Physics, is Energy in the form of waves or moving Subatomic particles emitted by an atom or other body as it changes from a higher energy A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half Somatic hypermutation (or SHM is a mechanism inside cells that is part of the way the immune system adapts to the new foreign elements which confront it (for example Mutations are considered the driving force of evolution, where less favorable (or deleterious) mutations are removed from the gene pool by natural selection, while more favorable (or beneficial) ones tend to accumulate. eVolution is the third Album by eLDee, it was due to be released in 2008 Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of Neutral mutations do not affect the organism's chances of survival in its natural environment and can accumulate over time, which might result in what is known as punctuated equilibrium; the modern interpretation of classic evolutionary theory. The neutral theory of molecular evolution is an influential theory that was introduced with provocative effect by Motoo Kimura in the late 1960s and early 1970s Punctuated equilibrium is a theory of evolutionary biology which states that most sexually reproducing populations experience little change for most of their geological
Causes of change in allele frequency
Main article: Population genetics
There are four known processes that affect the survival of a characteristic; or, more specifically, the frequency of an allele (variant of a gene):
- Mutation detailed above. Population genetics is the study of the Allele frequency distribution and change under the influence of the four evolutionary forces Natural selection, Genetic An allele (ˈæliːl (UK /əˈliːl/ (US (from the Greek αλληλος allelos, meaning each other) is one member of a pair or series of different forms History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance In biology mutations are changes to the Nucleotide sequence of the Genetic material of an organism
- Genetic drift describes changes in gene frequency that cannot be ascribed to selective pressures, but are due instead to events that are unrelated to inherited traits. In Population genetics, genetic drift is the accumulation of random events that change the makeup of a gene pool slightly but often compound over time This is especially important in small mating populations, which simply cannot have enough offspring to maintain the same gene distribution as the parental generation.
- Gene flow or Migration: or gene admixture is the only one of the agents that makes populations closer genetically while building larger gene pools. In Population genetics, gene flow (also known as gene migration) is the transfer of Alleles of Genes from one Population to another
- Selection, in particular natural selection produced by differential mortality and fertility. In the context of Evolution, certain traits or Alleles of a Species may be subject to selection Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of Differential mortality is the survival rate of individuals before their reproductive age. If they survive, they are then selected further by differential fertility – that is, their total genetic contribution to the next generation. In this way, the alleles that these surviving individuals contribute to the gene pool will increase the frequency of those alleles. Sexual selection, the attraction between mates that results from two genes, one for a feature and the other determining a preference for that feature, is also very important. Sexual selection is the Theory proposed by Charles Darwin that states that certain evolutionary traits can be explained by Intraspecific competition
Molecular study of phylogeny
Main articles: Molecular systematics, Phylogenetics
Molecular systematics is a product of the traditional field of systematics and molecular genetics. Biological systematics is the study of the diversity of Life on the planet Earth both past and present and the relationships among living things through time Molecular genetics is the field of Biology which studies the structure and function of Genes at a molecular level It is the process of using data on the molecular constitution of biological organisms' DNA, RNA, or both, in order to resolve questions in systematics, i. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units e. about their correct scientific classification or taxonomy from the point of view of evolutionary biology. Taxonomy is the practice and science of classification The word comes from the Greek, taxis (meaning 'order' 'arrangement' and, nomos Evolutionary biology is a sub-field of Biology concerned with the origin of Species from a Common descent, and Descent of species
Molecular systematics has been made possible by the availability of techniques for DNA sequencing, which allow the determination of the exact sequence of nucleotides or bases in either DNA or RNA. The term DNA sequencing encompasses biochemical methods for determining the order of the Nucleotide bases Adenine, Guanine, Cytosine Nucleotides are Organic compounds that consist of three joined structures a nitrogenous base a Sugar, and a Phosphate group At present it is still a long and expensive process to sequence the entire genome of an organism, and this has been done for only a few species. In classical genetics the genome of a Diploid Organism including Eukarya refers to a full set of chromosomes or genes in a Gamete, thereby However, it is quite feasible to determine the sequence of a defined area of a particular chromosome. A chromosome is an organized structure of DNA and Protein that is found in cells. Typical molecular systematic analyses require the sequencing of around 1000 base pairs. In Molecular biology, two Nucleotides on opposite complementary DNA or RNA strands that are connected via Hydrogen bonds are called
The driving forces of evolution
Main articles: Neutral theory of molecular evolution, Modern evolutionary synthesis, Mutationism
Depending on the relative importance assigned to the various forces of evolution, three perspectives provide evolutionary explanations for molecular evolution. The neutral theory of molecular evolution is an influential theory that was introduced with provocative effect by Motoo Kimura in the late 1960s and early 1970s Mutationism refers to the theories of Evolution where Mutations are the main driving force [1]
While recognizing the importance of random drift for silent mutations,[2] selectionists hypotheses argue that balancing and positive selection are the driving forces of molecular evolution. Those hypotheses are often based on the broader view called panselectionism, the idea that selection is the only force strong enough to explain evolution, relaying random drift and mutations to minor roles. [1]
Neutralists hypotheses emphasize the importance of mutation, purifying selection and random genetic drift. [3] The introduction of the neutral theory by Kimura,[4] quickly followed by King and Jukes' own findings,[5] lead to a fierce debate about the relevance of neodarwinism at the molecular level. Motoo Kimura (木村資生 Kimura Motoo) ( November 13, 1924 - November 13, 1994) was a Japanese biologist best known for introducing Jack Lester King ( March 9, 1934 &ndash June 29, 1983) was an American evolutionary biologist best known for co-authoring (with Thomas Hughes Jukes ( August 26, 1906 &ndash November 1, 1999) was a British-American biologist known for his work in Nutrition, Neo-Darwinism is a term used to describe certain ideas about the mechanisms of Evolution that were developed from Charles Darwin 's original Theory of The nearly neutral theory expanded the neutralist perspective, suggesting that several mutations are nearly neutral, which means both random drift and natural selection is relevant to their dynamics. [6][7]
Mutationists hypotheses emphasize random drift and biases in mutation patterns. [8] Sueoka was the first to propose a modern mutationist view. He proposed that the variation in GC content was not the result of positive selection, but a consequence of the GC mutational pressure. [9]
Related fields
An important area within the study of molecular evolution is the use of molecular data to determine the correct biological classification of organisms. This is called molecular systematics or molecular phylogenetics.
Tools and concepts developed in the study of molecular evolution are now commonly used for comparative genomics and molecular genetics, while the influx of new data from these fields has been spurring advancement in molecular evolution. Genomics is the study of an organism's entire Genome. The field includes intensive efforts to determine the entire DNA sequence of organisms and fine-scale Genetic
Key researchers in molecular evolution
Some researchers who have made key contributions to the development of the field:
- Motoo Kimura — Neutral theory
- Masatoshi Nei — Adaptive evolution
- Walter M. Fitch — Phylogenetic reconstruction
- Walter Gilbert — RNA world
- Joe Felsenstein — Phylogenetic methods
- Susumu Ohno — Gene duplication
- John H. Gillespie — Mathematics of adaptation
Journals and societies
Journals dedicated to molecular evolution include Molecular Biology and Evolution, Journal of Molecular Evolution, and Molecular Phylogenetics and Evolution. Motoo Kimura (木村資生 Kimura Motoo) ( November 13, 1924 - November 13, 1994) was a Japanese biologist best known for introducing Masatoshi Nei is Evan Pugh Professor of Biology at Pennsylvania State University and Director of the Institute of Molecular Evolutionary Genetics since 1990 Walter M Fitch is Professor of Molecular evolution at the University of California Irvine. Walter Gilbert (born March 21, 1932) is an American physicist, biochemist, and Molecular biology pioneer Joseph "Joe" Felsenstein is Professor in the Departments of Genome Sciences and Biology and Adjunct Professor in the Departments of Computer Science and Susumu Ohno ( February 1, 1928 &ndash January 13, 2000) was an Asian American Geneticist and Evolutionary biologist, and John H Gillespie is an Evolutionary biologist interested in theoretical population genetics and Molecular evolution. Research in molecular evolution is also published in journals of genetics, molecular biology, genomics, systematics, or evolutionary biology. Genetics (from Ancient Greek grc-Latn genetikos, “genitive” and that from grc-Latn genesis, “origin” a discipline of Biology, is Molecular biology is the study of Biology at a molecular level Genomics is the study of an organism's entire Genome. The field includes intensive efforts to determine the entire DNA sequence of organisms and fine-scale Genetic Biological systematics is the study of the diversity of Life on the planet Earth both past and present and the relationships among living things through time Evolutionary biology is a sub-field of Biology concerned with the origin of Species from a Common descent, and Descent of species The Society for Molecular Biology and Evolution publishes the journal "Molecular Biology and Evolution" and holds an annual international meeting.
See also
Further reading
- Li, W.-H. (2006). The history of molecular evolution starts in the early 20th century with "comparative biochemistry" but the field of Molecular evolution came into its own in the 1960s eVolution is the third Album by eLDee, it was due to be released in 2008 In Population genetics, genetic drift is the accumulation of random events that change the makeup of a gene pool slightly but often compound over time Evolutionary physiology is the study of physiological evolution, which is to say the manner in which the functional characteristics of individuals in a population of Organisms have a vast array of ways in which their respective Genomes are organized Human evolution, or anthropogenesis, is the part of biological Evolution concerning the emergence of Homo sapiens as a distinct Species The molecular clock (based on the molecular clock hypothesis ( MCH) is a technique in Molecular evolution to relate the divergence time of two Species Phylogenetic comparative methods (PCMs use information on the evolutionary relationships of organisms (phylogenetic trees to compare species (Harvey and Pagel 1991. The neutral theory of molecular evolution is an influential theory that was introduced with provocative effect by Motoo Kimura in the late 1960s and early 1970s Nucleotide diversity is a concept in Molecular genetics which is used to measure the degree of polymorphism within a population Parsimony is a 'less is better' concept of frugality economy stinginess or caution in arriving at a hypothesis or course of action In the context of Evolution, certain traits or Alleles of a Species may be subject to selection Population genetics is the study of the Allele frequency distribution and change under the influence of the four evolutionary forces Natural selection, Genetic Wen-Hsiung Li (1942- is a Taiwanese American scientist working in the fields of Molecular evolution, Population genetics, and Genomics. Molecular Evolution. Sinauer. ISBN 0878934804.
- Lynch, M. (2007). Michael Lynch (born 1951 is Distinguished Professor of Evolution, Population Genetics and Genomics at Indiana University. The Origins of Genome Architecture. Sinauer. ISBN 0878934847.
References
- ^ a b Graur, D. and Li, W. -H. (2000). Fundamentals of molecular evolution. Sinauer.
- ^ Gillespie, J. H (1991). John H Gillespie is an Evolutionary biologist interested in theoretical population genetics and Molecular evolution. The Causes of Molecular Evolution. Oxford University Press, New York. ISBN 0-19-506883-1.
- ^ Kimura, M. (1983). Motoo Kimura (木村資生 Kimura Motoo) ( November 13, 1924 - November 13, 1994) was a Japanese biologist best known for introducing The Neutral Theory of Molecular Evolution. Cambridge University Press, Cambridge. Cambridge University Press (known colloquially as CUP is a Publisher given a Royal Charter by Henry VIII in 1534 ISBN 0-521-23109-4.
- ^ Kimura, Motoo (1968). "Evolutionary rate at the molecular level". Nature 217: 624–626. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
- ^ King, J. L. and Jukes, T. H. (1969). "Non-Darwinian Evolution". Science 164: 788–798. Science is the Academic journal of the American Association for the Advancement of Science and is considered one of the world's most prestigious Scientific doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
- ^ Ohta, T (1992). "The nearly neutral theory of molecular evolution". Annual Review of Ecology and Systematics 23: 263–286. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
- ^ Ohta, T. (2002). Tomoko Ohta ( born 7 September 1933) is a Japanese scientist working on Molecular evolution. "Near-neutrality in evolution of genes and gene regulation". Proceedings of the National Academy of Sciences 99: 16134–16137. The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
- ^ Nei, M. (2005). Masatoshi Nei is Evan Pugh Professor of Biology at Pennsylvania State University and Director of the Institute of Molecular Evolutionary Genetics since 1990 "Selectionism and Neutralism in Molecular Evolution". Molecular Biology and Evolution 22(12): 2318–2342.
- ^ Sueoka, N. (1964). "On the evolution of informational macromolecules", in In: Bryson, V. and Vogel, H. J. : Evolving genes and proteins. Academic Press, New-York, 479-496.
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