HYBRIDIZATION EXPERIMENTS WITH ACHEILOGNATHINE FISHES (CYPRINIDAE). INTERGENERIG HYBRIDS BETWEEN PARACHEILOGNATHUS RHOMBEUS AND ACHEILOGNATHUS LANCEOLATUS

Abstract

The successful hybridization between Paracheilognathus rhombeus and Acheilognathus lanceolatus, both of Japanese origin, is reported.

Part of the F₁ hybrid offspring consisted of fully fertile females and males. However, two backcross progenies obtained by crossing the male hybrid between A. lanceolatus female and P. rhombeus male with females of both parental species respectively were sterile or partly so.

The F₁ larvae and the backcrosses showed lowered viability. This is attributed to the disturbance of the balance of their respective genomes.

A number of internal and external isolation mechanisms that probably effectively prohibit introgression in populations of both sympatric species are mentioned.