Sex control in cod

水产养殖是世界上增长最快的食品生产部门。在加拿大，捕捞渔业从1980年代后期的历史高点下降，水产养殖产量在过去十年中增加了十倍以上。加拿大大部分的水产养殖产量来自于在不列颠哥伦比亚省和新玩法养殖的鲑鱼。然而，在加拿大大西洋沿岸的大部分地区，鲑鱼并不适合水产养殖，鲑鱼水产养殖作为一个整体在加拿大很难保持盈利。因此，工业界和政府一致努力使加拿大大西洋沿岸的水产养殖多样化。大西洋鳕鱼被视为该地区的主要替代水产养殖物种，加拿大大西洋最大的水产养殖公司（库克水产公司）最近对鳕鱼养殖业进行了大量投资。他们的初步生产试验突出表明，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，从而有可能将大量的受精卵释放到野外，这一事实使这个问题变得更加复杂。我们建议开发实用的方法生产单一性别的鳕鱼种群，以利用性别相关的年龄和大小的差异在成熟，并连接到一个平行的研究计划，目前正在进行的生产三倍体（不育）鳕鱼。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逆转治疗方案的发展。性别决定的遗传机制将通过雌核发育来确定，由此阻止了父系基因组在可存活胚胎中的表达，并且母系基因组被复制。检查雌核发育种群后代的性别比例有助于确定性别决定的遗传基础，并为生产单一性别种群的最佳方法的决定提供信息。内分泌性逆转将被用来创造亲鱼能够产生单一性别的后代。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.