Evidences for a multiple sex chromosome system with female heterogamety in apareiodon affinis (Pisces, parodontidae)

Abstract

The karyotype of the fish Apereiodon affinis shows 2n = 54 chromosomes for the male and 2n = 55 chromosomes for the female. The data obtained suggest a mechanism of multiple sex chromosomes of the ZZ/ZW1W2 type, where chromosome Z may be number 1 in the complement and chromosomes W1 and W2 are morphologically undifferentiated. This is the first probable occurrence of this type of mechanism to be described for fishes. © 1980 Taylor & Francis Group, LLC.