Posted: Feb 07, 2017 8:26 pm
In the case of the ZW chromosome system, the homogametic individuals (ZZ) are male, whilst the heterogametic individuals (ZW) are female.
in the case of this shark, if the ability to produce viable diploid eggs was present, then the obvious choice is for the eggs to be heterogametic like their mother (ZW). It's a bit difficult to see how a Z and W chromosome could be swapped between eggs in order to facilitate the emergence of ZZ eggs, because [1] this would require a mechanism that as far as I'm aware, isn't known to exist by biologists, and [2] would have as a side effect producing non-viable WW eggs. That is, unless there are known instances of WW individuals being viable in species with this determination system.
in the case of this shark, if the ability to produce viable diploid eggs was present, then the obvious choice is for the eggs to be heterogametic like their mother (ZW). It's a bit difficult to see how a Z and W chromosome could be swapped between eggs in order to facilitate the emergence of ZZ eggs, because [1] this would require a mechanism that as far as I'm aware, isn't known to exist by biologists, and [2] would have as a side effect producing non-viable WW eggs. That is, unless there are known instances of WW individuals being viable in species with this determination system.