Dynamical genetics
Encyclopedia
Dynamical genetics concerns the study and the interpretation of those phenomena in which physiological enzymatic
protein complex
es alter the DNA
, in a more or less sophisticated way.
The study of such mechanisms is important firstly since they promote useful functions, as for example the immune system recombination
(on individual scale
) and the crossing-over
(on evolutionary scale
); secondly since they may sometimes become harmful because of some malfunctioning, causing for example neurodegenerative disorders.
Typical examples of dynamical genetics subjects are:
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
protein complex
Protein complex
A multiprotein complex is a group of two or more associated polypeptide chains. If the different polypeptide chains contain different protein domain, the resulting multiprotein complex can have multiple catalytic functions...
es alter the DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
, in a more or less sophisticated way.
The study of such mechanisms is important firstly since they promote useful functions, as for example the immune system recombination
V(D)J recombination
VJ recombination, also known as somatic recombination, is a mechanism of genetic recombination in the early stages of immunoglobulin and T cell receptors production of the immune system...
(on individual scale
Ontogeny
Ontogeny is the origin and the development of an organism – for example: from the fertilized egg to mature form. It covers in essence, the study of an organism's lifespan...
) and the crossing-over
Chromosomal crossover
Chromosomal crossover is an exchange of genetic material between homologous chromosomes. It is one of the final phases of genetic recombination, which occurs during prophase I of meiosis in a process called synapsis. Synapsis begins before the synaptonemal complex develops, and is not completed...
(on evolutionary scale
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
); secondly since they may sometimes become harmful because of some malfunctioning, causing for example neurodegenerative disorders.
Typical examples of dynamical genetics subjects are:
- dynamic mutationsThe Sherman paradoxThe Sherman Paradox refers to an anomalous pattern of inheritance found in Fragile X syndrome. The phenomenon is also referred to as anticipation or dynamic mutation....
, term introduced by Robert I. Richards and Grant R. Sutherland to indicate mutationMutationIn molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
s caused by other mutations; this phenomenon often involves the Variable Number Tandem Repeats, closely related to many neurodegenerative diseases, as the trinucleotide repeat disordersTrinucleotide repeat disordersTrinucleotide repeat disorders are a set of genetic disorders caused by trinucleotide repeat expansion, a kind of mutation where trinucleotide repeats in certain genes exceeding the normal, stable, threshold, which differs per gene...
(interpreted by Anita HardingAnita HardingAnita Harding was a British neurologist. She was born in Birmingham and educated at the King Edward VI High School for Girls and the Royal Free Hospital Medical School, where she qualified in 1975. She married neurology professor P.K...
). - dynamic genome, term introduced by Nina FedoroffNina FedoroffNina Vsevolod Fedoroff is an American professor at Penn State university known for her research in life sciences and biotechnology. She received in 2006 the National Medal of Science in the field of Biological Sciences, the highest award for lifetime achievement in scientific research in the...
and David Botstein to indicate the transpositionTransposonTransposable elements are sequences of DNA that can move or transpose themselves to new positions within the genome of a single cell. The mechanism of transposition can be either "copy and paste" or "cut and paste". Transposition can create phenotypically significant mutations and alter the cell's...
discovered by Barbara McClintockBarbara McClintockBarbara McClintock , the 1983 Nobel Laureate in Physiology or Medicine, was an American scientist and one of the world's most distinguished cytogeneticists. McClintock received her PhD in botany from Cornell University in 1927, where she was a leader in the development of maize cytogenetics...
. - immune V(D)J recombinationV(D)J recombinationVJ recombination, also known as somatic recombination, is a mechanism of genetic recombination in the early stages of immunoglobulin and T cell receptors production of the immune system...
(discovered by Susumu Tonegawa) and isotype class switchingAntibodyAn antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
, terms introduced to indicate two kinds of immune system recombinations, which are the main cause of the enormous variety of antibodies. - horizontal DNA transfer (discovered by Frederick GriffithFrederick GriffithFrederick Griffith was a British bacteriologist whose focus was the epidemiology and pathology of bacterial pneumonia. In January 1928 he reported what is now known as Griffith's Experiment, the first widely accepted demonstrations of bacterial transformation, whereby a bacterium distinctly...
) that indicates the DNA transfer between two organisms. - crossing-overChromosomal crossoverChromosomal crossover is an exchange of genetic material between homologous chromosomes. It is one of the final phases of genetic recombination, which occurs during prophase I of meiosis in a process called synapsis. Synapsis begins before the synaptonemal complex develops, and is not completed...
(discovered by Thomas Hunt MorganThomas Hunt MorganThomas Hunt Morgan was an American evolutionary biologist, geneticist and embryologist and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries relating the role the chromosome plays in heredity.Morgan received his PhD from Johns Hopkins University in zoology...
) mediated by formation and unwinding (by means of peculiar enzymatic complexes such as helicaseHelicaseHelicases are a class of enzymes vital to all living organisms. They are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands using energy derived from ATP hydrolysis.-Function:Many cellular processes Helicases are a...
) of uncommon four-helix DNA structures known as G-quadruplexG-quadruplexIn molecular biology, G-quadruplexes are nucleic acid sequences that are rich in guanine and are capable of forming a four-stranded structure...
es (discovered by Martin Gellert, Marie N. Lipsett, and David R. Davies).