Abstract
Haploid gynogenetic screens increase the efficiency of forward genetic screens and linkage analysis in fish. Typically, UV-irradiated zebrafish sperm is used to activate zebrafish oocytes for haploid screens. We describe the use of UV-irradiated common carp sperm to activate haploid gynogenetic zebrafish development. Carp × zebrafish hybrids are shown to have a characteristic set of features during embryonic development and exhibit functional development of several tissues (muscle, heart and nervous system). Hybrids become inviable past the embryonic stages. This technique eliminates the possibility of incompletely irradiated zebrafish spermatozoa contaminating haploid progenies. While developing this protocol, one unique zebrafish female was identified which, upon insemination with UV-irradiated carp spermatozoa, repeatedly displayed spontaneous diploidization of the maternal chromosomes in her offspring.