Estrogen oversees the maintenance of the female genetic program in terminally differentiated gonochorists B. Paul-Prasanth1,2*, R.K. Bhandari1,2,3*, T. Kobayashi4, R. Horiguchi1,2,3, Y. Kobayashi1,2,3, M. Nakamoto1,2, Y. Shibata1,2, F. Sakai1,2, M. Nakamura1,2* & Y. Nagahama1,2, 5* 1 Solution-Oriented Research for Science and Technology (SORST); 2Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan; 3Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Motobu 905-0227, Okinawa, Japan; 4Laboratory of Molecular Reproductive Biology, Institute of Shizuoka, Shizuoka 422-8526, Japan; 5South Ehime Fisheries Research Center, Ehime University, Matsuyama 790-8577, Japan *These authors have contributed equally To whom correspondence may be addressed: E-mail: nagahama.yoshitaka.mh@ehime-u.ac.jp, masaru@lab.u-ryukyu.ac.jp Supplementary Information Video legends Supplementary video 1. Normal male versus normal female. Pairing of a mature, normal female with a mature male elicits sexual behavior in the latter. The male displays various steps (refer to the supporting text) of the mating behavior like following, courtship orientation, dancing, floating, crossing etc and female remains cooperative and responsive. Supplementary video 2. Normal female versus normal female. Two females placed together in the same tank do not exhibit any particular behavior. Supplementary video 3. Normal female versus AI-treated female. AI-female starts to follow the normal female, like a normal male. Steps of male-specific sexual behavior like following and dancing can be seen clearly. However, courtship orientation and other steps are not clearly displayed by the AI-female probably due to the non-cooperative attitude of the normal female. Thus, pairing of the AI-female with a normal female never results in mating and gamete release. Supplementary video 4. Normal male with AI-female. AI-female assumes the dominant position and starts attacking the normal male. Interestingly, the normal male does not become subordinate, but it starts to exhibit the male-specific sexual behavior. However, the treated female continues to attack the normal male and the latter stops sexual behavior.