TWINS RAISED FROM SEPARATED BLASTOMERES DEVELOP INTO SEXUALLY MATURE STRONGYLOCENTROTUS-PURPURATUS

The first two blastomeres of Strongylocentrotus purpuratus embryos wer e separated and the resulting twins raised in pairs through larval lif e and to sexual maturity. We derive tyro conclusions from this study: changes in the pattern of specification of embryonic cell fates follow ing blastomere separation result in the creation of two sets of fully functional coelomic pouches and imaginal rudiments, and sex determinat ion in sea urchins is chromosomal, since the pairs of twins were alway s of the same sex. (C) 1996 Academic Press, Inc.