Viable nuclear-cytoplasmic hybrids are obtained by electrofusion

ABSTRACT Artificially induced fish gynogenesis is a special genetic and selective method for producing inbred lines or homozygous lines. Induced gynogenetic grass carp (Ctenopharyngodon idella) and silver carp (Hypophthalmichthys molitrix) were produced by use of ultraviolet rays for common carp sperm inactivation and cold shock for egg diploidization. Examination of serum esterases as genetic markers, using electrofocusing of thin-layer 5% polyacrylamide gels, demonstrated that the genetic material of induced gynogenetic grass carp and silver carp was from the maternal parent, and was not detected from the paternal parent. Sex reversal experiments were performed on 12-13-cm gynogenetic silver carp with lo-12 mg methyltestosterone released from silastic implants that were inserted in the fingerling. Changes of morphology and construction of the gonads resulted.

Viable nuclear-cytoplasmic hybrids are obtained by electrofusion

CHEN HONCXI,

LIU PEILIN,

YI YONGLAN

and LIU HANQIN

Institute of Hydrobiology, Academia Sinica, Wuhan (China)

ABSTRACT Nuclear-cytoplasmic hybrid fishes have been obtained from the combination of nucleus and cytoplasm between two intergeneric species of fresh-water teleosts using the technique of electric fusion, i.e. the combination of the nucleus of carp (Cyprinus carpio red variety) and the cytoplasm of crucian carp (Caroasius auratus red variety), and the combination of the nucleus of Paramisgurnus dabryanus 9 x Misgurnus anguillicaudatus d and the cytoplasm of loach (Misgurnus anguillicaudatus). Morphological characteristics of those hybrid fish that have been examined so far are similar to those of donor nucleus parental species. Some of the hybrid fish grow to normal adults.

Survival in the early fresh-water period in Atlantic salmon (S&no solar) and rainbow trout (S&no guirdneri): heritabilities for survival and genetic correlation between survival and growth

M. RYE’ and K.M. LILLEVIK’ ‘Institute of Aquaculture Research, P.O. Box 10. N-1432 AS-NLH (Norway) 2Felleskjopet Rogaland, N-4000 Stavanger (Norway)

ABSTRACT Heritabilities

for survival in five periods in the early fresh-water

phase and genetic correlations