On the Pattern of Mitosis in the Zygotes of Grass Carp, Silver Carp and their F₁ Hybrids

Abstract

As the progeny of the intergeneric cross between two Chinese carps, viz., grass carp (Ctenopharyngodon idella) and silver carp (Hypophthalmichthys molitrix), have been reported to exhibit poor viability in spite of compatibility in their diploid status, some investigations were made with regard to the pattern of mitosis in their zygotes in comparison to their parent species to understand and find out any deviation from the normal pattern in the mitosis of the zygote from those of the parent species. It was observed that the mitosis pattern in the hybrid zygote was though apparently similar to the parent species with regard to the arrangement of chromosomes on the equatorial plane and their movement towards the poles, the division of the parent cell into two daughter cells was mostly irregular and uneven.