Editing Halibut (section)

== Sex-determining genes ==
Halibut species vary in sex determination systems.<ref name="Edvardsen-2022">{{Cite journal |last1=Edvardsen |first1=Rolf Brudvik |last2=Wallerman |first2=Ola |last3=Furmanek |first3=Tomasz |last4=Kleppe |first4=Lene |last5=Jern |first5=Patric |last6=Wallberg |first6=Andreas |last7=Kjærner-Semb |first7=Erik |last8=Mæhle |first8=Stig |last9=Olausson |first9=Sara Karolina |last10=Sundström |first10=Elisabeth |last11=Harboe |first11=Torstein |last12=Mangor-Jensen |first12=Ragnfrid |last13=Møgster |first13=Margareth |last14=Perrichon |first14=Prescilla |last15=Norberg |first15=Birgitta |date=2022-02-08 |title=Heterochiasmy and the establishment of gsdf as a novel sex determining gene in Atlantic halibut |journal=PLOS Genetics |language=en |volume=18 |issue=2 |pages=e1010011 |doi=10.1371/journal.pgen.1010011 |issn=1553-7404 |pmc=8824383 |pmid=35134055 |doi-access=free }}</ref> The Atlantic halibut went down a purely XX/XY route, with the male being heterogametic, around 0.9 to 3.8 million years ago. The sex-determining gene for the Atlantic halibut is likely to be gsdf on chromosome 13.<ref name="Edvardsen-2022" /> The Pacific halibut went down a ZZ/ZW route, with the female being heterogametic, around 4.5 million years ago.<ref name="Edvardsen-2022" /><ref>{{Cite journal |last1=Einfeldt |first1=Anthony L. |last2=Kess |first2=Tony |last3=Messmer |first3=Amber |last4=Duffy |first4=Steven |last5=Wringe |first5=Brendan F. |last6=Fisher |first6=Jonathan |last7=den Heyer |first7=Cornelia |last8=Bradbury |first8=Ian R. |last9=Ruzzante |first9=Daniel E |last10=Bentzen |first10=Paul |date=July 2021 |title=Chromosome level reference of Atlantic halibut Hippoglossus hippoglossus provides insight into the evolution of sexual determination systems |url=https://onlinelibrary.wiley.com/doi/10.1111/1755-0998.13369 |journal=Molecular Ecology Resources |language=en |volume=21 |issue=5 |pages=1686–1696 |doi=10.1111/1755-0998.13369 |pmid=33655659 |bibcode=2021MolER..21.1686E |s2cid=232101415 |issn=1755-098X}}</ref> The master sex-determining gene of the Pacific halibut is located on chromosome 9 and it is likely to be ''bmpr1ba.''<ref>{{Cite journal |last1=Jasonowicz |first1=Andrew J. |last2=Simeon |first2=Anna |last3=Zahm |first3=Margot |last4=Cabau |first4=Cédric |last5=Klopp |first5=Christophe |last6=Roques |first6=Céline |last7=Iampietro |first7=Carole |last8=Lluch |first8=Jérôme |last9=Donnadieu |first9=Cécile |last10=Parrinello |first10=Hugues |last11=Drinan |first11=Daniel P. |last12=Hauser |first12=Lorenz |last13=Guiguen |first13=Yann |last14=Planas |first14=Josep V. |date=October 2022 |title=Generation of a chromosome-level genome assembly for Pacific halibut ( Hippoglossus stenolepis ) and characterization of its sex-determining genomic region |journal=Molecular Ecology Resources |language=en |volume=22 |issue=7 |pages=2685–2700 |doi=10.1111/1755-0998.13641 |issn=1755-098X |pmc=9541706 |pmid=35569134|bibcode=2022MolER..22.2685J }}</ref> The gene ''sox2'' is likely to play the same role in the Greenland halibut.