Multiple haemoglobins in three tilapiine species of the genus Oreochromis and in eight strains of O. niloticus (L.)

摘要

AbstractAmong three tilapiine species,Oreochromis aureus(Steindachner),O mossambicus(Peters) andO. niloticus(L.), fifteen banding positions of haemoglobin were resolved using citric acid‐aminopropylmorpholine pH 7.0 buffer.O. mossambicusandO. aureusdisplayed 7 and 8 fixed band locations, respectively, whereas eight strains ofO. niloticusfrom Asian cultured and African wild populations showed a total of 14. Variability in theO. niloticusstrains, manifested as presence or absence of haemoglobin bands, was observed in banding positions 3, 4, 6, 7, 8, 9, 10, 13 and 14. Six banding positions inO. niloticuswere shared withO. mossambicusand 8 withO. aureus.A dendrogram constructed from distance coefficients between popu‐lation pairs using the presence or absence data showed the close affinity among O.niloticusstrains belonging to theO. niloticus niloticussubspecies. A slight separation of KenyaO. niloticusfrom theO. niloticus niloticusstrains is consistent with its subspecific distinction asO. niloticus vulcani.Among three species,O. niloticushad a closer affinity toO. aureusthan toO. mossambicus.The phylogenetic relation‐ships using differences in haemoglobin patterns and the higher genetic variability ofO. niloticusreflect similar results obtained from existing studies using allozymes. In general, the presence of multiple fish haemoglobins is attributed to their adaptability to haeterogeneous environments. This attribute is typical of til