Inheritance of reproductive traits of medicinal leeches (Hirudo medicinalis L.)

The phenotype variability and inheritance of reproductive traits were investigated in the medicinal leech. Distribution parameters were determined for the following traits: batch size (X = 4.3 +/- 0.2, sigma = 1.7, CV = 40%, As = 0.23 +/- 0.25, Ex = 0.19 +/- 0.51), number of juveniles in a cocoon (X = 10.9 +/- 0.3, sigma = 4.6, CV = 42%, As = 0.31 +/- 0.15, Ex = 0.23 +/- 0.30), and juvenile weight (X = 32.0 +/- 0.3, sigma = 14.9, CV = 47%, As = 1.38 +/- 0.05, Ex = 3.32 +/- 0.11. A nonlinear negative correlation between the number of juveniles in a cocoon and their weight was found (correlation ratio R = 0.86). It was shown that the environmental variance dominated over the genotypic one in the structure of phenotypic variance of the traits studied. The genetic variability is determined mainly by additive gene interactions and, to a small extent, intralocus dominance. The narrow-sense heritability, h2, for batch size was 0.35-0.40; for the number of juveniles in a cocoon, 0.35; for juvenile weight, 0.42.