If Y eggs had
been generated, the female to male ratio in the donor-derived F1 fish
group would have been 1:3 (XY × XY = 1XX + 2XY + 1YY, namely 1
female to 3 males; Fig. 1B). In the present study, we examined 16
randomly selected donor-derived F1 fish. Out of those 16 F1 fish, we
found 3 females and 13 males. The female:male ratio (3:13) was very
close to the theoretically expected one (4:12) if we assumed that Y
eggs had been produced.