The Production of Spontaneous Melanotic Neoplasms in Fishes by Selective Matings: II. Neoplasms with Macromelanophores Only. III. Neoplasms in Day Old Fishes

摘要: Introduction In previous work it has been shown that when a spotted platyfish ( Platy-poecilus maculatus ) is mated with Mexican swordtail Xiphophorus hellerii melanosis develops in all those hybrids which inherit the spotting factor from their parent. When parent homozygous for SpSp ), hybrids; whereas if heterozygous Spsp one-half of are melanotic and other half normal. The two types melanophores—one type, smaller, called micromelanophores, inherited as an autosomal dominant, large macromelanophores, sex-linked dominant (Gordon 1927). Both may be, usually are, present single individual, though genetic strains have developed only one or type melanophore present. A number different hybrid combinations possible between reference to content. The listed below, together incidence particular hybrid. It evident above table Fig. 1 that, transmits macromelanophores offspring, do these offspring develop melanosis. Platyfish micro- but alone combined hereditary factors sufficient bring young. In cases figure, had micro-melanophores. following experiments describe results sword-tails without melanophores used parents offspring.