Mutation

Mutation (pronounced myoo-tey-shuhn)

(1) In biology (also as “break”), a sudden departure from the parent type in one or more heritable characteristics, caused by a change in a gene or a chromosome.

(2) In biology, (also as “sport”), an individual, species, or the like, resulting from such a departure.

(3) The act or process of mutating; change; alteration.

(4) A resultant change or alteration, as in form or nature.

(5) In phonetics (in or of Germanic languages), the umlaut (the assimilatory process whereby a vowel is pronounced more like a following vocoid that is separated by one or more consonants).

(6) In structural linguistics (in or of Celtic languages), syntactically determined morphophonemic phenomena that affect initial sounds of words (the phonetic change in certain initial consonants caused by a preceding word).

(7) An alternative word for “mutant”

(8) In cellular biology & genetics, a change in the chromosomes or genes of a cell which, if occurring in the gametes, can affect the structure and development of all or some of any resultant off-spring; any heritable change of the base-pair sequence of genetic material.

(9) A physical characteristic of an individual resulting from this type of chromosomal change.

(10) In law, the transfer of title of an asset in a register.

(11) In ornithology, one of the collective nouns for the thrush (the more common forms being “hermitage” & “rash”)

1325–1375: From the Middle English mutacioun & mutacion (action or process of changing), from the thirteenth century Old French mutacion and directly from the Latin mūtātion- (stem of mūtātiō) (a changing, alteration, a turn for the worse), noun of action from past-participle stem of mutare (to change), from the primitive Indo-European root mei- (to change, go, move).  The construct can thus be understood as mutat(e) +ion.  Dating from 1818, the verb mutate (to change state or condition, undergo change) was a back-formation from mutation.  It was first used in genetics to mean “undergo mutation” in 1913.  The –ion suffix was from the Middle English -ioun, from the Old French -ion, from the Latin -iō (genitive -iōnis).  It was appended to a perfect passive participle to form a noun of action or process, or the result of an action or process. The use in genetics in the sense of “process whereby heritable changes in DNA arise” dates from 1894 (although the term "DNA" (deoxyribonucleic acid) wasn't used until 1938 the existence of the structure (though not its structural detail) was fist documented in 1869 after the identification of nuclein).  In linguistics, the term “i-mutation” was first used in 1874, following the earlier German form “i-umlaut”, the equivalent in English being “mutation”.  The noun mutagen (agent that causes mutation) was coined in 1946, the construct being muta(tion) + -gen.  The –gen suffix was from the French -gène, from the Ancient Greek -γενής (-genḗs).  It was appended to create a word meaning “a producer of something, or an agent in the production of something” and is familiar in the names of the chemical elements hydrogen, nitrogen, and oxygen.  From mutagen came the derive forms mutagenic, mutagenesis & mutagenize.  Mutation, mutationist & mutationism is a noun, mutability is a noun, mutable & mutant are nouns & adjectives, mutated & mutating are verbs & adjectives, mutational & mutationistic are adjective and mutationally is an adverb; the noun plural is mutations.  For whatever reasons, the adverb mutationistically seems not to exist.

In scientific use the standard abbreviation is mutat and forms such as nonmutation, remutation & unmutational (used both hyphenated and not) are created as required and there is even demutation (used in computer modeling).  In technical use, the number of derived forms is vast, some of which seem to enjoy some functional overlap although in fields like genetics and cellular biology, the need for distinction between fine details of process or consequence presumably is such that the proliferation may continue.  In science and linguistics, the derived forms (used both hyphenated and not) include animutation, antimutation, backmutation, e-mutation, ectomutation, endomutation, epimutation, extramutation, frameshift mutation, hard mutation, heteromutation, homomutation, hypermutation, hypomutation, i-mutation, intermutation, intramutation, intromutation, macromutation, macromutational, megamutation, mesomutation, micromutation, missense mutation, mixed mutation, multimutation, mutationless, mutation pressure, nasal mutation, neomutation, nonsense mutation, oncomutation, paramutation. Pentamutation, phosphomutation. point mutation, postmutation, premutation, radiomutation, retromutation, soft mutation, spirant mutation, stem mutation, stereomutation, ultramutation & vowel mutation.

Ginger, copper, auburn & chestnut are variations on the theme of red-headedness: Ranga Lindsay Lohan demonstrates the possibilities.

Red hair is the result of a mutation in the melanocortin 1 receptor (MC1R) gene responsible for producing the MC1R protein which plays a crucial role also in determining skin-tone. When the MC1R gene is functioning normally, it helps produce eumelanin, a type of melanin that gives hair a dark color.  However, a certain mutation in the MC1R gene leads to the production of pheomelanin which results in red hair.  Individuals with two copies of the mutated MC1R gene (one from each parent) typically have red hair, fair skin, and a higher sensitivity to ultraviolet (UV) light, a genetic variation found most often in those of northern & western European descent.

A mutation is a change in the structure of the genes or chromosomes of an organism and mutations occurring in the reproductive cells (such as an egg or sperm), can be passed from one generation to the next.  It appears most mutations occur in “junk DNA” and the orthodox view is these generally have no discernible effects on the survivability of an organism.  The term junk DNA was coined to describe those portions of an organism's DNA which do not encode proteins and were thought to have no functional purpose (although historically there may have been some).  The large volume of these “non-coding regions” surprised researchers when the numbers emerged because the early theories had predicted they would comprise a much smaller percentage of the genome.  The term junk DNA was intentionally dismissive and reflected the not unreasonable assumption the apparently redundant sequences were mere evolutionary “leftovers” without an extant biological function of any significance.

However, as advances in computing power have enabled the genome further to be explored, it’s been revealed that many of these non-coding regions do fulfil some purpose including: (1) A regulatory function: (the binary regulation of gene expression, influencing when, where, and how genes are turned on or off; (2) As superstructure: (Some regions contribute to the structural integrity of chromosomes (notably telomeres and centromeres); (3) In RNA (ribonucleic acid) molecules: Some non-coding DNA is transcribed into non-coding RNA molecules (such as microRNAs and long non-coding RNAs), which are involved in various cellular processes; (4) Genomic Stability: It’s now clear there are non-coding regions which contribute to the maintenance of genomic stability and the protection of genetic information.  Despite recent advances, the term junk DNA is still in use in mapping but is certainly misleading for those not immersed in the science; other than in slang, in academic use and technical papers, “non-coding DNA” seems now the preferred term and where specific functions have become known, these regions are described thus.

There’s also now some doubt about the early assumptions that of the remaining mutations, the majority have harmful effects and only a minority operate to increase an organism's ability to survive, something of some significance because a mutation which benefits a species may evolve by means of natural selection into a trait shared by some or all members of the species.  However, there have been suggestions the orthodox view was (at least by extent) influenced by the slanting of the research effort towards diseases, syndromes and other undesirable conditions and that an “identification bias” may thus have emerged.  So the state of the science now is that there are harmful & harmless mutations but there are also mutations which may appear to have no substantive effect yet may come to be understood as significant, an idea which was explored in an attempt to understand why some people found to be inflected with a high viral-load of SARS-Cov-2 (the virus causing Covid-19) remained asymptomatic.

In genetics, a mutation is a change in the DNA sequence of an organism and it seems they can occur in any part of the DNA and can vary in size and type.  Most associated with errors during DNA replication, mutations can also be a consequence of viral infection or exposure to certain chemicals or radiation, or as a result of viral infections.  The classification of mutations has in recent years been refined to exist in three categories:

(1) By the Effect on DNA Sequence:  These are listed as Point Mutations which are changes in a single nucleotide and include (1.1) Substitutions in which one base pair is replaced by another, (1.2) Insertions which describe the addition of one or more nucleotide pairs and (1.3) Deletions, the removal of one or more nucleotide pairs.

(2) By the Effect on Protein Sequence: These are listed as: (2.1) Silent Mutations which do not change the amino acid sequence of the protein, (2.2) Missense Mutations in which there is a change one amino acid in the protein, potentially affecting its function, (2.3) Nonsense Mutations which create a premature stop codon, leading to a truncated and usually non-functional protein and (2.4) Frameshift Mutations which result from insertions or deletions that change the reading frame of the gene, often leading to a completely different and non-functional protein.

(3) By the Effect on Phenotype: These are listed as (3.1) Beneficial Mutations which provide some advantage to the organism, (3.2) Neutral Mutations which have no apparent significant effect on the organism's fitness and (3.3) Deleterious Mutations which are harmful to the organism and can cause diseases or other problems.

(4) By the Mechanism of Mutation: These are listed as (4.1) Spontaneous Mutations which occur naturally without any external influence, due often to errors in DNA replication and (4.2) Induced Mutations which result from exposure to mutagens environmental factors such as chemicals or radiation that can cause changes in DNA),

Because of the association with disease, genetic disorders and disruptions to normal biological functions, in the popular imagination mutations are thought undesirable.  They are however a crucial part of the evolutionary process and life on this planet as it now exists would not be possible without the constant process of mutation which has provided the essential genetic diversity within populations and has driven the adaptation and evolution of species.  Although it will probably never be known if life on earth started and died out before beginning the evolutionary chain which endures to this day, as far as is known, everything now alive (an empirically, that means in the entire universe) ultimately has a single common ancestor.  Mutations have played a part in the diversity which followed and of all the species which once have inhabited earth, a tiny fraction remain, the rest extinct.

Nuclear-induced mutations

Especially since the first A-Bombs were used in 1945, the idea of “mutant humans” being created by the fallout from nuclear war or power-plants suffering a meltdown have been a staple for writers of science fiction (SF) and producers of horror movies, the special-effects and CGI (computer generated graphics) crews ever imaginative in their work.  The fictional works are disturbing because radiation-induced human mutations are not common but radiation can cause changes in DNA, leading to mutations and a number of factors determine the likelihood and extent of damage.  The two significant types of radiation are: (1) ionizing radiation which includes X-rays, gamma rays, and particles such as alpha and beta particles.  Ionizing radiation has enough energy to remove tightly bound electrons from atoms, creating ions and directly can damage DNA or create reactive oxygen species that cause indirect damage.  In high doses, ionizing radiation can increase the risk of cancer and genetic mutations and (2) non-ionizing radiation which includes ultraviolet (UV) light, visible light, microwaves, and radiofrequency radiation.  Because this does not possess sufficient energy to ionize atoms or molecules, which there is a risk of damage to DNA (seen most typically in some types of skin cancer), but the risk of deep genetic mutations is much lower than that of ionizing radiation.  The factors influencing the extent of damage include the dose, duration of exposure, the cell type(s) affected, a greater or lesser genetic predisposition and age.

Peter Dutton (b 1970; leader of the opposition and leader of the Australian Liberal Party since May 2022) announces the Liberal Party's new policy advocating the construction of multiple nuclear power-plants in Australia.

The prosthetic used in the digitally-altered image (right) was a discarded proposal for the depiction of Lord Voldemort in the first film version of JK Rowling's (b 1965) series of Harry Potter children's fantasy novels; it used a Janus-like two-faced head.  It's an urban myth Mr Dutton auditioned for the part when the first film was being cast but was rejected as being "too scary".  If ever there's another film, the producers might reconsider and should his career in politics end (God forbid), he could bring to Voldemort the sense of menacing evil the character has never quite achieved.  Interestingly, despite many opportunities, Mr Dutton has never denied being a Freemason.

On paper, while not without challenges, Australia does enjoy certain advantages in making nuclear part of the energy mix: (1)  With abundant potential further to develop wind and solar generation, the nuclear plants would need only to provide the baseload power required when renewable sources were either inadequate or unavailable; (2) the country would be self-sufficient in raw uranium ore (although it has no enrichment capacity) and (3) the place is vast and geologically stable so in a rational world it would be nominated as the planet's repository of spent nuclear fuel and other waste.  The debate as it unfolds is likely to focus on other matters and nobody images any such plant can in the West be functioning in less than twenty-odd years (the Chinese Communist Party (CCP) gets things done much more quickly) so there's plenty of time to squabble and plenty of people anxious to join in this latest theatre of the culture wars.  Even National Party grandee Barnaby Joyce (b 1967; thrice (between local difficulties) deputy prime minister of Australia 2016-2022) has with alacrity become a champion of all things nuclear (electricity, submarines and probably bombs although, publicly, he seems not to have discussed the latter).  The National Party has never approved of solar panels and wind turbines because they associate them with feminism, seed-eating vegans, homosexuals and other symbols of all which is wrong with modern society.  While in his coal-black heart Mr Joyce's world view probably remains as antediluvian as ever, he can sniff the political wind in a country now beset by wildfires, floods and heatwaves and talks less of the beauty of burning fossil fuels.  Still, in the wake of Mr Dutton's announcement, conspiracy theorists have been trying to make Mr Joyce feel better, suggesting the whole thing is just a piece of subterfuge designed to put a spanner in the works of the transition to renewable energy generation, the idea being to protect the financial positions of those who make much from fossil fuels, these folks being generous donors to party funds and employers of "helpful" retired politicians in lucrative and undemanding roles.