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V A Geodakian

Publications and source records attributed to V A Geodakian.

14 recordsLinked to original sources
PubMed1998

[Evolutionary role of sex chromosomes (a new concept)].

Sex differentiation provides for testing evolutionary innovations in the male genome before they are transferred to the female genetic system. This is possible with dichronous (asynchronous) evolution, when evolution in males precedes that in females [3-7]. Hence, along with common autosomal genes for stable characters, exclusively male and exclusively female genes must exist. The male genes are already acquired by the male genome but are not yet transferred to the female one. The female genes are already lost by the male genome but still remain in the female genome. They constitute temporary evolutionary genotypic sexual dimorphism. Common genes cannot exhibit genotypic sexual dimorphism; they show only constant phenotypic hormonal sexual dimorphism. On the basis of the interpretation of genotypic sexual dimorphism as a consequence of sex dichronism, the evolutionary role of sex chromatins is clarified and a new concept for them is suggested. According to this concept, the Y chromosome is the "conductor" of ecological information into the genome, the "place of birth" and testing of new genes, the accelerator and regulator of genotypic sexual dimorphism. By contrast, the X chromosome of the heterogametic sex provides the transportation of new genes from the Y chromosome to autosomes. This chromosome stabilizes, relaxes, and suppresses genotypic sexual dimorphism and accumulates genes that will be eliminated. This concept sheds light on many problems: the chromosomal localization of genes and their transfer to other chromosomes, the inactivation of chromosomes, mobile genes, mutation bursts, insertional mutagenesis, the association of the Y chromosome with stress, retroviruses, etc. In particular, it explains why genes "jump," why transpositions of mobile elements depend on ecological stress, why different genes mutate simultaneously, etc.

Biological Evolution↗
PubMedDate not supplied

[Evolutionary chromosomes and sex dimorphism].

In order to understand the phenomenon of sex, it is not enough to know about its reproductive role and role in recombination. In addition, knowledge of its evolutionary role is required. Sexual differentiation allows us to test evolutionary innovations in the male genome before they are transmitted to the female genome. This is possible in the framework of dichronous evolution, when the evolution of the male sex goes faster than the evolution of the female sex. This implies that there clearly should be male genes, which are already present in the male genome, but are not yet in the female genome; and vice versa, there should exist female genes, which have already been lost by the male sex, but still remain in females. Dichronicity results from different reaction norm of the sexes. This interpretation implies (1) the nomadic behavior of genes in the genome (2) the existence of evolutionary sexual dimorphism, which begins in the form of modificational changes in the female sex followed by selection-derived changes in the male sex; (3) the discovery of evolutionary roles of chromosomes and the proposition of a new concept, according to which the Y-chromosome represents a "gateway" for environment-related information coming to the genome, i.e., place of "birth" and testing of new genes, which comprise the basis of evolutionary sexual dimorphism--its initiator, accelerator, and regulator. The X-chromosome is the "transport" chromosome that transfers new genes from the Y-chromosomes into autosomes and therefore serves as a stabilizer, relaxer, and liquidator of evolutionary sexual dimorphism; it also serves as repository of the outgoing genes that await elimination. This concept provides for a new interpretation of the appearance, localization, and movement of genes along chromosomes and between them, and it sheds new light on the phenomena of chromosomal inactivation, mobile genes, association of Y-chromosome with stress, viruses, etc.

Animals↗
PubMedDate not supplied

[Evolutionary theories of asymmetrization of organisms, brain and body].

Growth of a dispersion of elements of unitary systems (US) inevitably transfrorms them into the binary connected differentiations (BCD). So, at a level of genes, from bisexuals have arisen females and males, and at a level of hormones (mentality, behavior), from symmetric--asymmetric: functions, organs, right-handers and left-handers. All BCD are isomorphic. They consist of subsystems preservation (conservative) and change (operative) (SP, SC). SP is more important, than SC, therefore the dispersion of their elements is less, than elements SC. This base difference. It transforms a monomodal population in bimodal, direct "ecology, (environment, E US), in consequetn (E SC SP), and synchronous evolution in asynchronous (at first SC, later SP). Then for evolution "pay" only SC. Means, asynchronous evolution is more economical, than synchronous. In it adaptive sense of any BCD. All theories of biology are theories of US. They treat subsystems not as phased but as forms, therefore may not explain BCD. The general idea of asynchronous evolution--control centre of any function arises in the left hemisphere and in the right hemisphere gets only after approbation. Hence, creates asymmetry different phases of the same function in the left and right hemisphere, but not different functions. It has allowed to reject a lot of erroneous representations and to create adaptive, internally consistent, evolutionary theories of three-demensional asymmetry of organisms, a brain, a cis-trans asymmetry of pair organs and dextrality-sinistrality, having unique explanatory and predictive potential.

Adaptation, Physiological↗
PubMedDate not supplied

[Asynchronous asymmetry (sexual and lateral differentiation--a consequence of asynchronous evolution)].

In the paper is presented a unified interpretation of sex differentiation and lateral asymmetry as asynchronous evolution. The operative subsystems, i.e. the male and the left hemisphere of the brain evolutionize earlier than the conservative ones, i.e. the female and the right hemisphere. New functions appear at first in males and after many generations they are transferred to females. The leading centers of their control are at first originated in the left hemisphere, then they are translocated to the right one. The criterion for functions localization in the hemisphere is their evolutionary age: new functions are controlled by the left hemisphere, old functions by the right one. Therefore the left hemisphere is socio-cultural, ethnic, the right one is biological, special. The theory explains from a single standpoint the phenomena of sex, handedness, nervous crossover, as well as many know facts, and predicts the new ones.

Animals↗