Zeitschrift für Fischkunde Band 8 Heft 1/2 15.10.2006 S. 99-100 Kurze Mitteilung/Short note Buxeus, a new colour gene in the guppy, Poecilia reticulata PETERS, 1859 (Teleostei, Cyprinodontiformes) Buxeus, ein neues Farbgen beim Guppy, Poecilia reticulata PETERS, 1859 (Teleostei, Cyprinodontiformes) Michael Kempkes Am Mühlenberg 25, D-46419 Isselburg-Anholt Zusammenfassung: Ein gelb-grünes, metallisch schillerndes Farbmerkmal, genannt Buxeus, wird von Poecilia reticulata beschrieben. Wie die Ergebnisse vor allem reziproker Paarungen mit bekannten Stämmen nahe legen, wird dieses Merkmal, das nur adulte Männchen zeigen, vom Y-Chromosom kodiert. Genetic investigations in the guppy (Poecilia reticulata) have a long tradition. The guppy is probably the first species in which a colour gene strictly linked to the Y-chromosome was discovered (SCHMIDT 1920, WINGE 1922a, b, 1927). In the course of its domestication numerous phenotypes and colour genes have been described and studied (e.g.,DZWILLO 1959, NAYADU 1979, FERNANDO & PHANG 1990, PHANG et al. 1990, PHANG & FERNANDO 1990, 1991, KHOO et al. 1999a, b, c). In 1997 I received a strain of guppies whose males were characterised by a yellow-green metallic colour extending from the head to nearly the base of the caudal fin including the neck and back. The unpaired fins, often coloured in domesticated guppy strains, are slightly white or transparent (fig. 1). Females are uncoloured. I named this strain Buxeus (buxeus lat. = yellow-green).To study the mode of inheritance of this remarkable colouring a series of crosses with two guppy strains, Pauper (cf. WINGE 1927) and Maculatus (cf. WINGE 1922b) were performed. In both strains the characteristic colouring of males is determined by loci on the Y-chromosome; females are not coloured (WINGE 1922, 1927; pers. obs.) and, therefore, resemble phenotypically the Buxeus females. All strains were kept at 27 °C in 120 l aquaria, planted with Cryptocoryne sp. They were fed with Artemia salina, Daphnia spec., crushed Spirulina and high quality flake food. For each cross two males and two females were mated and kept in 45-l aquaria under similar conditions. The offspring of each breeding was raised separately until the colouring was fully developed. The crosses (males first, female last) gave the following results: A1: Pauper x Buxeus. F1: 92 males (all Pauper), 99 females (uncoloured). A2: F1 from Pauper x Buxeus. F2: 72 males (all Pauper), 104 females (uncoloured). A3: F1 from Pauper x Buxeus x Buxeus. 75 males (all Pauper), 80 females (uncoloured). B1: Maculatus x Buxeus. F1: 160 males (all Maculatus), 198 females (uncoloured). B2: F1 from Maculatus x Buxeus. F2: 48 males (all Maculatus), 61 females (uncoloured). B3 F1 from Maculatus x Buxeus x Buxeus: 29 males (all Maculatus), 33 females (uncoloured). C1: Buxeus x Pauper. F1: 82 males (all Buxeus), 103 females (uncoloured). C2: F2 (F1 x F1): 122 males (all Buxeus), 101 females (uncoloured). D1: Buxeus x Maculatus. F1: 133 males (all Buxeus), 146 females (uncoloured). D2: F2 (F1 x F1): 20 males (all Buxeus), 34 females (no colour marks). As seen from the results Buxeus appeared exclusively when a male of this phenotype was Z. Fischk. Bd. 8 Heft 1/2 99 Fig. 1: Male of the strain Buxeus. Abb. 1: Männchen mit dem Farbmerkmal “Buxeus”. involved. This strongly indicates that this phe- KHOO, G., T. M. LIM, W.-K- CHAN, & V. P. E. PHANG. 1999b. Sex-linkage of the black caudal-peduncle notype is Y-linked. Moreover, in all back crosses and red tail genes in the tuxedo strain of the gup(A2, B2) and interbreedings (C2, D2) producing py, Poecilia reticulata. Zool. Sci. 16, 629-638. an F2, the phenotype is inherited exclusively from KHOO, G., T. M. LIM, W.-K- CHAN, & V. P. E. PHANG. the father to the sons. Therefore, Buxeus appears 1999c. Linkage analysis and mapping of three not to be caused by an autosomal factor, indicasexlinked color pattern genes in the guppy, Poeciting again the Y-linked inheritance. lia reticulata. Zool. Sci. 16, 893-903. Acknowledgements I thank Horst SCHIMMELPFENNIG, who discovered these guppies in his aquarium and kindly donated them in 1997 for the present study. I thank Harald AUER for the strains Pauper and Maculatus donated in the year 1999. Many thanks also to Fred N. POESER (University Amsterdam) for his support. Literature DZWILLO, M. 1959. Genetische Untersuchungen an domestizierten Stämmen von Lebistes reticulatus (PETERS). Mitt. Zool. Inst. Mus. Hamburg 57, 143-186. FERNANDO, A. A., & V. P. E. PHANG. 1990. 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The genetic behaviour of a secondary sexual character. C. R. Trav. Lab. Carlsberg 14, 1-12. WINGE, Ö. 1922a. A peculiar mode of inheritance and its cytological explanation. J. Genet. 12, 145162. WINGE, Ö. 1922b. One-sided masculine and sexlinked inheritance in Lebistes reticulatus. J. Genet. 13, 201-219. WINGE, Ö. 1927. The location of eighteen genes in Lebistes reticulatus. J. Genet. 18, 1-43. Eingegangen: 28. 06. 2005 Angenommen: 18. 12. 2005 100