Language and genetics

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The Linguogenetik (lat = lingua tongue language, and generate gignere =.) Is an interdisciplinary linguistics , which examines the emergence of speech in two ways:

overview

As a phylogenetic science, the emergence of language is traced in the course of life over about 800 million years. Comparative anatomy and molecular biological studies of the so-called language genes are primarily involved. As an ontogenetic science, she is primarily interested in the development of language in human or animal life (cf. Pinker 1998).

Linguogenetics should not be confused with language family research of humanities provenance . The comparative comparison of the national languages ​​around the world leads to findings about the relationship in the development of human languages ​​over the past 100,000 years. In this respect, it also contributes to questions and certain approaches in the field of linguogenetics. However, the purely linguistic methodology for experimental research into language genes and their expression in a human-animal comparison seems rather inefficient.

history

Johann Gottfried Herder on a painting by Anton Graff , 1785

Historically, the writing on the “Origin of Language” by Johann Gottfried Herder should be noted. “Even as animals, humans have language”: this is Herder's first sentence, which in 1771 had a shocking effect on the theologians of his time. Herder speculates on a future state of science in which the details of the phylogeny of language would be known. In any case, he observes that because of his weak sense perception, humans are forced to develop lexicons , syntax and morphology in the typical human way. In birds and older mammals, he observes emotional expressions of speech, which he describes as "primordial poetry". Human language art must imitate these primal forces of emotional expression in order to arrive at an artistic work. This original poetry can be found especially in folk songs, sagas, ballads and other “original” forms.

Like Herder, a French- language zoologist born in 1744 is Jean Baptiste Lamarck . In his writings on the philosophy of the biological, he primarily postulates the inheritance of what has been learned. Using the example of the giraffe, he shows that the attempt to reach higher and higher for food has gradually been successful in the body structure of the animals. The typically human ability to acquire the complete language within a few years can be traced back to the inheritance of what has been learned.

Charles Darwin has opposed this theory of the inheritance of learned skills in his writings on the origin of man. Development takes place through mutation - that is, “accidental” change in the genetic material (in neo-Darwinism, the DNA is understood as the carrier of the genetic material). If mutations lead to traits that enable the individual to survive better and reproduce more successfully, the mutation in question is retained. Otherwise it leads to disease and dies out over the millennia.

Darwin's theses have been confirmed in the linguistic genetics of the natural sciences through two so-called dogmas:

  • the Cajal dogma
  • and the Weismann barrier.
  1. Santiago Ramón y Cajal had evidence that no new nerve cells form in humans after birth. Since language is only acquired after birth, in Cajal's view, language learning cannot establish itself in the daughter cells of the nerves.
  2. August Weismann believed that he had proven that acquired traits in the individual were not reproduced in the genome. Accordingly, language can only ever be passed on from the living to young individuals. They are not inherited.

Both dogmas were partially refuted in the 1990s:

  1. Research into brain stem cells has shown that - especially in the hippocampus - pluripotent cells in the vicinity of nerve cells differentiate into real nerve cells (Kempermann 2008).
  2. The experimental exploration of the Weismann barrier has led to the detection of inherited immunological abilities in mice, so that the Weismann objection to the inheritance of language also became obsolete (cf. Steele et al. 1998).

Finally, we managed to clone a number of genes that are correlated with language functions. The ZENK gene first became known from songbird research (cf. Jarvis 2000). Birds that had sung shortly before they were experimentally killed showed increased concentrations of the ZENK gene in the cytoplasm. It was then possible to modify the UBE3A gene in mice in the same way as is known in human autistic diseases (cf. Albrecht et al. 1997). The transgenic mice showed autistic behavior. Finally, genes were found that correlate with motor language weakness (FOXP2, Parkinson's group). In the area of ​​language cognition, too, genes have been cloned: especially the dyslexia genes (cf. Tzenova 2004) and the autism genes (cf. Autism Genome Project 2007) are trend-setting.

Due to the development outlined above, contemporary linguogenetics is focused on the detection of further language genes and on the exploration of the expression of these genes (cf. gene expression analysis ). Of particular interest is the possibility of influencing these genes in the context of therapies for children and old people with language disorders.

Phylogeny of Language

By comparing the morphology of the speech and language organs, the development of language from unicellular to recent humans has been described. In addition, there is the molecular genetic comparison of language genes with mice, songbirds and microorganisms , so that humans can also look into what Lorenz calls the “back” of the mirror with regard to language development . The aim of these phylogenetic language studies is above all a better understanding of human language: why is language needed and what are the limits of language performance in humans and animals? Subsequently, the question of epistemology becomes significant, which is answered in phylogenetic epistemology to the effect that each species only knows as much of the truth as is compatible with survival for it.

Morphology of the speech and language organs

The comparison with Pan Troglodytes (chimpanzees) aroused particular interest in this context . Because of its far-advanced jaw, his irregular teeth stock and its flat throat one is articulating very difficult in terms of human language. However, the best-known gene for speech motor skills is almost identical to that in humans. On the other hand, the chimpanzee is particularly suitable for cognitive operations in the sense of human language, so that it can be taught arithmetic and reading better than any other species (see Premack ).

Molecular genetics

First ornithologists discovered the ZENK gene (Jarvis et al. 2000). Songbirds were killed while they were singing and the activity of the ZENK gene in the cytoplasm was examined. It was very active in the area of ​​the two language centers for language motor skills and language sensors. Then you deafened the birds and made them sing. Now the gene was only active in the area of ​​the primary speech center. After all, the animals were only allowed to listen to artificially processed singing by conspecifics. Accordingly, the Center for Language Sensing was now active.

A mutation on the UBE3A gene is known to cause Angelman syndrome if it occurs on the maternal chromosome 15q11-13 and possibly other positions. The result is severe autism of the Angelmann disease type. That is why mice have been implanted with the corresponding mutation ( transgenic ) and antisocial behavior has been described in the carriers of this mutation (cf. Albrecht et al. 1997).

Gene cloning, often celebrated as the birth of linguogenetics, affects the FOXP2 gene. It was found in 2001 in two families with autosomal dominant inherited speech dyspraxia (poor speech acquisition) (Lai et al. 2001). The gene has been found in chimpanzees, mice and even songbirds and is surprisingly conserved in spite of the obvious differences in the articulation abilities of humans and animals (same base triplets, see Enard et al. 2002).

The first decade of the 21st century is full of more discoveries in the field of linguogenetics. Autism genes, dyslexia genes, dementia genes from various clinical pictures were cloned (determination of the base structure). In addition, there are genes that affect diseases with severe speech symptoms: Parkinson's, Alzheimer's, Niemann-Pick, etc. Of course, the discovery of the genes only lays the foundation for further exploration of the genes in their expression during speech, hearing and reading. and writing process.

Since one has learned to stimulate or throttle the expression of genes with the help of so-called SIRNAs ( short interference RNAs ), therapeutic manipulation of the language genes is in prospect.

Epistemology

Konrad Lorenz (r.) And Nikolaas Tinbergen , 1978

Following Lorenz (1973), the question was asked whether the typically human language-mediated approach to truth shows that each species only understands as much of the so-called truth as is compatible with survival. According to this, even a devastating bang - be it chemical, nuclear or infectious - would be a testimony to the fact that a species with too much knowledge of "truth" does not survive.

Ontogeny of language

Through an empirical study of language acquisition by human and animal individuals, many details of language development have been explored and prepared for standardized testing . Today, such findings are followed by countless methods of promoting speech development and speech therapy for senile and presenile language diseases.

First of all, intrauterine language development should be used as the focus of recent linguogenetics. Here, both the development of the speech and speech organs and the modification of hearing comprehension in the last 2 months of pregnancy must be taken into account (cf. Karmiloff 2010).

In the first year of life, the non-verbal and paraverbal aspects of language development dominate. In no way can the concept of prelingual infant development be maintained. Another main aspect of this developmental period lies in the examination of hearing, since considerable impairment of language acquisition was observed in the first year of life due to overlooked hearing loss .

The countless genetic syndromes ( trisomy 21 , autism syndromes, other trisomies and monosomies, etc.) form a focus of linguogenetics in the first year of life (cf. Herrmann 1993). The constant diagnosis of development progress must be coordinated with the language development promotion by the parents and counselors.

In the second and third year of life, the classic sections of phonetic, semantic and syntactic language development are diagnosed and supervised. Added to this are the aspects of narcissistic disorders and the Oedipus conflict that have been researched in depth psychology. Toilet training also contains significant linguistic components.

The time of kindergarten is linguistically dominated by studies of the educational style ( Mead 1968). Above all, aggressiveness and sexual abuse were considered pathologically . There are considerable impairments in language acquisition here, which are hardly taken into account in routine healthcare. According to the requirement of symptomatic treatment, speech therapy becomes a contraindication in these cases.
In the pre-school period, bilingualism and the early diagnosis of reading and writing disorders are also examined or carried out in order to prevent school problems.

Primary school is largely a theme of language and literature didactics. Only the pathological phenomena are reserved for linguogenetics. In particular, linguogenetic research focuses on stuttering and fear of school in addition to caring for dyslexic or hyperkinetic children.
In the higher school age, linguistic research focuses on children and young people with disabilities and their school and extracurricular care. Due to better medical care, the life expectancy of this group has increased compared to the first half of the 20th century, which is why differentiated procedures for additional care have been established.

Presenile dementia (Down's disease, Alzheimer's type I, Huntington's syndrome, etc.) begins as early as the age of 30 . Due to the discoveries in the field of epigenetic research (gene expression stop or stimulation) and the monoclonal antibodies, the treatment of dementia patients has entered a new phase. Ultimately, logopedic intervention has a wider chance of being used because the disease progresses more slowly.

Linguogenetics is responsible for the area of ​​language involution (decay of language) in three ways:

  1. Early diagnosis : if speech involvement is recognized early, speech-preserving therapy is indicated.
  2. Palliation : After an incurable illness that leads to death is determined, speech-preserving therapy may be indicated that accompanies the patient until he dies .
  3. Aphasia care: Sudden loss of speech is a common complication after traumatic brain injuries (motorcycle accidents etc.) and strokes (apoplexy). Early diagnosis and treatment are the focus of linguistic research into aphasic language diseases.

literature

  • U. Albrecht, JS Sutcliffe, BM Cattanach, CV Beechey, D. Armstrong, G. Eichele, AL Beaudet: Imprinted Expression of the Murine Angelman Syndrome Gene, UBE3A, in Hippocampal and Purkinje Neurons. In: Nature Genetics . Volume 17, No. 9, 1997, pp. 75-78.
  • Autism Genome Project Consortium. Mapping autism risk loci using genetic linkage and chromosomal rearrangements. In: Nature Genet. Volume 39, 2007, pp. 319-328. (Note: Erratum: Nature Genet. Volume 39, 2007, p. 1285 only)
  • SR Cajal: Recollections of my life. Translated by Horne Craigie with Juan Cano of Recuerdos de mi vida. MIT Press, 1989.
  • Charles Darwin: The Origin of Species. (= New American Library ). Mentor Edition, 1958.
  • W. Enard, M. Przeworski, SE Fisher, CS Lai, V. Wiebe, T. Kitano, AP Monaco, S. Paabo: Molecular evolution of FOXP2, a gene involved in speech and language. In: Nature. Volume 418, 2002, pp. 869-872.
  • Herder, Johann Gottfried: Treatise on the origin of language. In: L. Schneider, W. Schleuning (Ed.): Sturm und Drang. Critical Writings. 1962.
  • Wolfgang Herrmann: The language acquisition of the child with cleft lip and palate. In: German journal for oral, maxillofacial and facial surgery. Volume 13, 1989, pp. 87-94; Volume 14, 1990, pp. 71-80; Volume 15, 1991, pp. 382-392.
  • Erich Jarvis, Claudio V. Mello: Molecular Mapping of Brain Areas Involved in Parrot Vocal Communication. In: The Journal of Comparative Neurology. Volume 419, 2000, pp. 1-31.
  • K. Karmiloff, A. Karmiloff-Smith: Getting to know your baby. Carroll & Brown, London 2010.
  • CS Lai, ES Fisher, JA Hurst, F. Vargha-Khadem, AP Monaco: A Forkhead-Domain Gene Is Mutated in a Severe Speech and Language Disorder. In: Nature . Volume 413/4, 2001, pp. 519-523.
  • Jean Baptiste Lamarck: Zoological Philosophy. Translated by Hugh Elliot. University of Chicago Press, Chicago 1809.
  • Konrad Lorenz : The back of the mirror. Piper, Munich 1973.
  • George Herbert Mead : Mind, Self, and Society. Ed. Charles W. Morris. Chicago 1934. (German translation: Spirit, identity and society from the perspective of social behaviorism. Suhrkamp-Verlag, Frankfurt am Main 1968)
  • Svante Pääbo : The Mosaic that is Our Genome. In: Nature. 421, 2003, pp. 409-412.
  • Steven Pinker : The language instinct. How the mind forms language. Kindler, Munich 1996.
  • Edward Steele, Robyn A. Lindley, Robert V. Blanden: Lamarck's Signature. How Retrogenes Are Changing Darwin´s Selection Paradigm. Massachusetts 1998.
  • J. Tzenova, BJ Kaplan, TL Petryshen, LL Field: Confirmation of a dyslexia susceptibility locus on chromosome 1p34-p36 in a set of 100 Canadian families. In: Am. J. Med. Genet. Volume 127B, 2004, pp. 117-124.

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