Abstracts

Genetic Bases of Biodiversity

In quantitative genetics decay of phenotypic variance of one quantitative trait in several components, caused of common and partial factors influence, as a rule, named a multidimensional analysis (Mather, Jinks, 1971). Rarely integrate inheritance of many traits, by examples, principal components (Polyakov et al., 1978), which not less may be named as multidimensional analysis, is analysed.

Let Р₁ and Р₂ - two parent inbred strains and F₁ - first hybrid generation, in which m quantitative traits are measured. In simplest additive-dominant model without interallelic interaction average value of every trait of F₁ - x_i^F1 = a_i + h_i , where a_i = (x_i^P1 + x_i^P2)/2 - average between parents, h_i - dominant deviation (Mather, Jinks, 1971).

Set x^F = (x^F1, x^F2, ... , x^Fm) - point in multidimensional space, which is average traits values for every generation (F = P₁, P₂, F₁). Points x^P1, a, x^P2 and x^F1 forms a triangle. Any line combination of traits - direction in trait space - is a trait too (selection index), along which a selection, in principle, is possible. But displacement of samples along straight line a and F₁ is caused only geterozygosis and will disappear in next generations. Obviously, geterozygous displacement of samples in projection on any direction, ortogonal to geterozygosis axe, is absent and this direction is for the most part additive-heritable.

Laboratory rats samples (P₁, P₂, F₁), in which 17 quantitative traits are measured. were analysed by this method. Distinctions between P₁-P₂ and F₁ (heterosis) are in sizes, but a direction of this distinctions is ortogonal to distinctions between P₁ and P₂, which are distinctions in forms of brain part of cranium. Thus the multidimensional genetic analysis after first hybridization already allow to define perspective directions to selection in multidimensional traits space.

LITERATURE

Polyakov Yu.F., Gindilis V.M., Kritckaya V.P., Meleshko T.K. Multidimensional methods using in genetic analysis of some characteristics of cognitive processes in schizophrenia. In: Problems of human genetic psychophysiology. Moscow, Nayka(Science), 1978, P.222-243. (in Russian)

Mather K., Jinks J.L, 1971. Biometrical genetics. The study of continuous variation. 2nd ed. Ithaca -N.Y., Cornell U.P.

Note. Abstracts are published in author's edition

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