Sex control in cod

水产养殖是世界上增长最快的粮食生产部门。在加拿大，捕捞渔业已从20世纪80年代末的历史高位下降，但水产养殖产量在过去十年中增加了十倍以上。加拿大大部分水产养殖产品来自不列颠哥伦比亚省和新不伦瑞克省养殖的鲑鱼。然而，在加拿大大西洋的大部分地区，鲑鱼并不适合水产养殖，在加拿大，鲑鱼水产养殖作为一个整体很难保持盈利。因此，工业界和政府共同努力，使加拿大大西洋地区的水产养殖多样化。大西洋鳕鱼被视为该地区的主要替代水产养殖品种，加拿大大西洋最大的水产养殖公司（库克水产养殖公司）最近对鳕鱼水产养殖进行了重大投资。他们的初步生产试验强调，生产鱼的早熟是商业可行性的一个关键制约因素，因为成熟的鱼停止生长，肉质下降，死亡率高。鳕鱼很容易在笼子里产卵，因此可能会将大量受精卵释放到野外，这使问题更加复杂。我们建议开发单性别鳕鱼种群生产的实用方法，以利用成熟时年龄和大小的性别相关差异，并与目前正在进行的三倍体（不育）鳕鱼生产的平行研究项目相联系。我们的研究将确定大西洋鳕鱼性别决定的遗传基础，并将导致该物种功能性性别逆转的治疗方案的发展。性别决定的遗传机制将由雌核发生决定，即父系基因组在可存活的胚胎中的表达被阻止，而母系基因组被复制。检查雌性生殖群体后代的性别比例有助于确定性别决定的遗传基础，并为产生单性别群体的最佳方法提供信息。然后，内分泌性别逆转将用于创造能够产生单性后代的亲鱼。将资助两名研究生进行这项研究。

Aquaculture is the world's fastest growing food production sector. In Canada, where capture fisheries have declined from historic highs in the late 1980s, aquaculture production has increased more than ten-fold in the last decade. Most of Canada's aquaculture production comes from salmon farmed in British Columbia and New Brunswick. However, salmon are not well suited for aquaculture in most of Atlantic Canada and salmon aquaculture as a whole has had difficulty remaining profitable in Canada. As a result, there is a concerted effort by industry and government to diversify aquaculture in Atlantic Canada. Atlantic cod is seen as a prime alternative aquaculture species for the region, and Atlantic Canada's largest aquaculture company (Cooke Aquaculture Inc.) has recently made significant investments into cod aquaculture. Their preliminary production trials have highlighted early maturation of production fish as a key constraint to commercial viability, because mature fish cease growing, have reduced flesh quality and have high mortality rates. This problem is compounded by the fact that cod will eadily spawn in cages, thereby potentially releasing large numbers of fertilized eggs into the wild. We propose to develop practical approaches for the production of single-sex populations of cod, in order to take advantage of sex-related differences in age and size at maturity, and to link into a parallel research program currently underway on the production of triploid (sterile) cod. Our research will determine the genetic basis to sex determination in Atlantic cod and will lead to the development of treatment regimes for functional sex reversal in this species. The genetic mechanism of sex determination will be determined y gynogenesis, whereby expression of the paternal genome in viable embryos is prevented and the maternal genome is duplicated. Examining sex ratios of the offspring from gynogenetic populations helps to identify the genetic basis of sex determination and informs the decision on best approaches for producing single-sex populations. Endocrine sex reversal will then be used to create broodstock capable of generating single-sex progeny. Two graduate students will be funded to conduct this research.