The Biology and Culture of Tilapias

S. niloticus x S. aureus hybrids

S. aureus

-68 (8,9)

-80 (A)

-6s (8)

-77 (6)

-80 (A)

Plate 2. Electropherogram of S. aureus in Plate 3. Electropherogram of S. niloticus^9
6% polyacrylamide gel. Individuals pre- x S. aureus d hybrids in 6% polyacrylamide
senting xenogeneic bands (arrow) are nor- gel. All the possible transferrin combina-
mally eliminated from the breeding stocks. tions are found in F1 hybrids. (A) = Albu-
(A) = Albumin; (9) (8) are transferrins; the min; (6) (8) are transferrins; the figures are
figures are % relative mobilities. % relative mobilities.

S. niloticus (Vulcani)

(-I S. nil. (V.) S. aureus S. niloticus (Ghana)

Plate 4. Differential identification of the selected mono-

morphic lines of Sarotherodon spp. From left to right: S.

niloticus (Vulcani) where band 9 presents the higher

density, S. aureus, where band 8 is constantly present and

S. niloticus (Ghana) where band 7 is quantitatively more

intense than the other transferrins.