Studies in inheritance in the hybridPhilosamia (Attacus) ricini (Boisd) ♂ × Philosamia cynthia (Drury) ♀
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The plain or non-spotted condition of the larva ofP. ricini is recessive to the spotted condition of the larva ofP. cynthia (Ning-po variety).
The dominance in the F1 generation is incomplete; all the larvae are spotted but not all have the full complement of spots.
The spots are probably represented, not by one, but by a group of related gens in the chromosome.
The dominant homozygous and the heterozygous forms can be distinguished only by breeding, as both may be either full- or partly-spotted.
A number of abnormal larvae with reduced tubercles occurred in the F2 generation; when mated with normal larvae, this character behaved as a recessive; whether it was a mutation which occurredde novo as a result of this particular cross or whether it is a result always to be expected from this hybrid, has not yet been determined. This non-tubercled mutation (?) is interesting in relation to the few non-tubercled species among the Saturniids.
KeywordsBlack Spot Natural Size Smooth Form Heterozygous Form Plate VIII
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