A. R. Luria and the Twin Method in Modern Medical Genetics


The twin method is one of the classical methods of medical genetics which aids in defining the role of factors of heredity and environment in traits of norm and pathology, to study development of multifactorial diseases and development of genetics of intellectual activity. From the genetic point of view twins may be either monozygotic or dizygotic. The field of intellectual activity, in particular learning ability, attention and memory is most difficult and inaccessible for the genetic analyses of twins. The very beginning of research of twins’ intellectual activity was laid by A.R. Luria in years 1920-1930 and the features of development of twins of various age were
revealed. Using tasks that required mental capacities of different levels: immediate memory vs cultural forms of mediated memory, Luria’s group compared results of monozygotic and dizygotic twins of different ages (5-7 and 11-13). It has been shown that monozygotic twins are much more similar between themselves concerning
mental capacities, natural forms of memory than dizygotic twins. In the older group it was the same difference in natural forma, but much less difference between monozygotic and dizygotic tweens in culturally determined forms of memory. Much more similarity was observed between monozygotic twins who grew separately, than
between dizygotic, being raised in the identical social environment. During these researches a number of assumptions have been stated about « the influence of heredity on intellectual activity which will be revealed in the solution of tasks which don’t demand special knowledge». Prospects of modern researches are in comparison of concordance mono-and dizygotic twins, confirming A. R. Luria’s assumption of interrelation of natural memory and intellectual endowments of twins with their genotype. Medical genetics confirms
that the extent of development of various intellectual traits of monozygotic and dizygotic twins is caused first of all by influence of the environment – training and experience which is revealed is increased in increased variability of most intellectual characteristics at the age of 14–16 years.

Keywords: A.R.Luria, twin method, medical genetics, epigenetic changes.

[1] Fando, R.A. (2015). Institut e‘ksperimental‘noj biologii i pervy‘e issledovaniya po genetike cheloveka.

[2] Ozernyuk, N.D. (2007). Odna istoriya dvux institutov // Priroda.10. S. 4-8.

[3] Ravich-Shherbo, I.V, Maryutina, T.M., Grigorenko, E.L. (2000).Psixogenetika: Ucheb. dlya studentov vuzov, obuchayushhixsya po special‘nosti i napravleniyu ”Psixologiya”. M.: Aspekt Press, S.447.

[4] Garfield E. Twins. Part 2. The twin study method in behavioral and clinical research. (1984). Essays of an Information Scientist. 7. pp. 397-404.

[5] Luria A. R., Yudovich F. Ya.(1956). Rech‘ i razvitie psixicheskix processov u rebenka. M.

[6] Mario F. Fraga, Esteban Ballestar, Maria F. Paz, et al. (2005). Epigenetic differences arise during the lifetime of monozygotic twins. PNAS 102 (30) pp.10604-10609.

[7] Monalisha S, Prasuna J. G. (2016). Twin Studies: A Unique Epidemiological Tool. Indian J Community MedJul-Sep. 41(3). pp.177–182.

[8] Wong, AH, Gottesman, I, Petronis, A. (2005). Phenotypic differences in genetically identical organisms: the epigenetic perspective. Hum. Mol. Genet. 1. pp.11-18.

[9] Rideout, WM, Eggan, K, Jaenisch, R. (2001). Nuclear cloning and epigenetic reprogramming of the genome.Science. 293(5532). pp.1093-8.

[10] Castillo-Fernandez, J.E, Spector, T. D, Bell J.T. (2014). Epigenetics of discordant monozygotic twins: implications for disease. Genome Med. 6(7): 60.

[11] Cardno, A. G., Rijsdijk, F. V., Sham, et al. (2002) A twin study of genetic relationships between psychotic symptoms. Am. J. Psychiatry 159, pp. 539-545.