Abraxas

ABRAXAS (a sacred word or "blessed name"), a cabalistic word expressing, by the numerical value of the Greek letters, the collective concept of 365 heavenly realms, in which, by analogy with the 365 days in a year, the deity manifests. Abraxas serves as an amulet and is found on gems, rings, and other talismans of early Christianity.

ABRAXAS, a genus of moths from the family Geometridae (looper moths). A representative of this genus, A. grossulariata L. (the currant moth, a pest of gooseberries and currants), served to clarify the mechanism of sex inheritance. Besides the ordinary A. grossulariata, white with black and yellow spots, females of a lighter color, so-called lacticolor, are occasionally encountered. When crossing lact. ♀ with gross. ♂, all individuals in the first generation (F₁) are of the gross. type. If ♂ from F₁ are crossed with lact. ♀, an equal number of gross. and lact. individuals are obtained, with an equal number of ♂♂ and ♀♀ in each type. In these crosses, inheritance strictly follows Mendel's laws, with the colors of the gross. and lact. types being allelomorphs, and the gross. type being dominant. If a male of the lact. type, obtained from the last cross, is crossed with a pure ♀ of the gross. type, not all will be gross. as one would expect, but an equal number of gross. and lact., with all ♂♂ being gross. and all ♀♀ being lact.. Such a deviation from Mendel's laws can be explained by assuming that the female produces two types of germ cells: some containing the germ (gene) determining wing color, others not containing it, with ♀♀ developing from the latter and ♂♂ from the former; in ♂♂, all germ cells are identical and contain the genes determining wing color. In the experiment with crossing gross. with lact., the resulting ♀♀ will have only one color gene from the father, therefore they will be lact.; the ♂♂ will possess two genes: from the father (lact.) and from the mother (gross.); gross. is dominant over lact., therefore all ♂♂ will be gross.. The absence of lact. ♂♂ in nature is explained by the low probability of a lact. ♀ meeting a male possessing the lact. gene. Thus, it is necessary to assume that the female A. grossulariata is heterozygous (produces two types of germ cells), while the male is homozygous (produces one type of germ cell), and sex inheritance occurs according to Mendel's laws (a case of so-called backcrossing: of a heterozygous form with a homozygous one). At first, this assumption could not be proven cytologically for A. gross.: both ♂♂ and ♀♀ had 56 chromosomes in somatic cells, therefore 28 in germ cells. However, recently it has been possible to find a race with 55 chromosomes in ♀ (therefore with 27 and 28 in germ cells). Obviously, in ordinary ♀♀ of A. gross., one of the chromosomes is inactive, since its absence does not affect the race with 55 chromosomes. A whole series of experiments of this kind was later conducted on the Drosophila fly, where the ♂ is heterozygous and where heterozygosity is clearly expressed in the chromosomes (there are X- and Y-chromosomes).