Within vertebrates. major sex determining genes can differ among taxa and even within species. In zebrafish (Danio rerio). neither heteromorphic sex chromosomes nor single sex determination genes of large effect. https://www.roneverhart.com/Western-Digital-Ultrastar-DC-HC550-WUH721816ALE6L0-0F38460-16TB-7-2K-RPM-SATA-6Gb-s-512e-ISE-3-5in-Hard-Drive/