Genetic analysis of scale chromatophores of two domesticated varieties of the guppy, Poecilia reticulata
1985
Phang, V.P.E. | Chow, O.K. | Fernando, A.A. (National University of Singapore (Singapore). Dept. of Zoology)
The background body colouration of the guppy, Poecilia reticulata results from the presence of chromatophores in the epidermis of the scales. Distinct differences in type, number and shape of scale melanophores, xanthophores and erythrophores were found between the wild type (WT), Blue tail (BT) and the Red tail (RT) strains. Erythrophores were present only in RT males. Wild-type guppies had low numbers of melanophores and xanthophores. Blue tail males had very high density of melanophores in the caudal peduncle. BT and RT females had about three times as many xanthophores in the flank region below the dorsal fin than WT females. The shape of melanophores was the least variable in the WT and most variable in the BT. Melanophore and xanthophore numbers in the F1 progeny of reciprocal crosses between selected variety and WT were phenotypically wild-type thus establishing the dominance of normal pigmentation over both BT and RT body colours. The si1045milarity between F1 progeny of reciprocal crosses give evidence to autosomal inheritance. Whether the genes determining BT and RT body colouration are allelic or independent needs to be tested by examining F2 offspring and performing crosses between BT and RT. The presence of erythrophores in RT males and F1 males of crosses between RT females and WT males demonstrates an X-linked, sex-limited mode of inheritance. Penetrance was not complete as indicated by very few erythrophores in F1 pro
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