Offspring of Sex-reversed Males in Bufo viridis LAUR

Ueda Hiroaki

Scientific report of the Laboratory for Amphibian Biology

In order to determine the sex-determining mechanism in Bufo viridis, males were sex-reversed into females by castration and subsequent administration with estrogen, and mated with normal males to obtain the offspring. Of the 25 castrated and estrogen-injected males, 17 lived for more than 15 months. While seven of these toads had regenerated testes and normal BIDDER'S organs, the other ten had well-developed ovaries transformed from their BIDDER'S organs, although the oviducts were defective in five of them. By pituitary injection, four of the remaining five sex-reversed males laid 473,62,5368 and 7316 eggs. By insemination with sperm of regenerated testes, 822 eggs attained completion of metamorphosis. Among 784 offspring, there were 197 females and 587 (74.9%) males. These numbers seem to show that the male in Bufo viridis is heterogametic (XY) and YY toads produced from matings between sexreversed genetic males (XY) and normal males (XY) can survive and become males.

Zoology [ 480 ]

eng

Institute for Amphibian Biology, Hiroshima University

[Created] 2006-03-21

[ISSN] 0386-3166

[NCID] AA00837669