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Updated: Oct 2, 2026

Preparation of Meiotic Chromosome Spreads from Zebrafish Spermatocytes
Published on: March 3, 2020
Identification of putative sex chromosomes in the blue tilapia, Oreochromis aureus, through synaptonemal complex and
R Campos-Ramos1, S C Harvey, J S Masabanda
1Institute of Aquaculture, University Stirling, Scotland.
Abstract:
Sex determination in the blue tilapia, Oreochromis aureus, is primarily a ZW female-ZZ male system. Here, by analysis of the pachytene meiotic chromosomes of O. aureus, we demonstrate the presence of two distinct regions of restricted pairing present only in heterogametic fish. The first, a subterminal region of the largest bivalent is located near to the region of unpairing found in the closely related species O. niloticus, while the second is in a small bivalent, most of which was unpaired. These results suggest that O. aureus has two separate pairs of sex chromosomes.
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