a) Stick appeared as a simple recessive mutation in the third season culture of 1919. The family in which the mutants were discovered was F10 generation of a hybrid between a Japanese bivoltine white (four molts, pale-quail marking) and a Chinese univoltine yellow (three molts, plain-skinned). b) The body of the stick caterpillar is thin and stiff and is easily distinguishable from normal by inspection. The growth of stick is always slower than that of normal. c) A greater percentage of stick is lost during the larval development than of normal. This accounts for the deficient numbers of sticks observed in experiments. The survivorship of stick is inferior to normal roughly by 5%. The differential viabilty is however, scarcely noted in favorable conditions. d) Multilunar and stick are linked in inheritance, and the crossingover between them is proved to be about 25.8%. It has been shown that Multilunar is inherited independently from the genes of the first, second and third linkage groups (TANAKA 1916, 1922, OGURA 1922), thus it forms, with stick, a fourth linkage group in the silkworm.
Mendeley出力
