Utevskaya O.M. Genetical analysis of the reproductive characters of the medicinal leech. - Manuscript.
Theses for a biology candidate degree, speciality 03.00.15 - genetics / Kharkov National University, Kharkov, 2000
The phenotypic variation and inheritance of the reproductive characters of the medicinal leeches (Hirudo medicinalis) were studied. Parameters of distributions were obtained for the following characters: number of cocoons per a clutch, number of hatchlings per a cocoon, weight of hatchlings. It was found that there is the nonlinear negative correlation between the number of hatchlings per a cocoon and weight of hatchlings (r = -0.4). It was established that the enviromental variance is more then the genotypic variance for all characters. The additive component prevails in the genotypic variance, the degree of the dominance is low. The coefficient of heritability for the number of cocoons per a clutch is 0.35-0.40, the number of hatchlings per a cocoon - 0.35, weight of hatchlings - 0.42. The optimums of the reproductive characters were determined and considered as selection limits. The possibility of correlated responses to selection for pair of characters "number of hatchlings per a cocoon - weight of hatchlings" was estimated. The results of different types of artifical selection were forecasted, the complex of the selection arrangements was elaborated in order to raise the fecundity of the medicinal leech.
Key words: medicinal leech, Hirudo medicinalis, reproduction, cocoons, hatchlings, heritability, selection.
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