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The chromosome numbers of Georgian earthworms (Oligochaeta: Lumbricidae)

Bakhtadze N.G., Bakhtadze G.I., Kvavadze E.Sh.

Abstract. The data on chromosome numbers (somatic and basic) characteristic to species and subspecies of earthworms (Lumbricidae) of Georgia (Caucasus region) are summarized. Four values of basic chromosome number (11, 15, 17, 18) while 6 values of somatic number (22, 30, 34, 36, 72, 108) are registered in 19 species and subspecies studied. The diploid karyotypes dominate over polyploid karyotypes. It is supposed that the modal numbers, somatic 2n=36 and basic n=18, are evolutionarily initial on the basis of which the formation of the main part of species and subspecies of earthworms have proceeded in Georgia. Polyploidy did not represent the main evo-lutionary mechanism of the origin of species in Georgia (and the whole Caucasus).