The physiology of polyploid fish

本研究的目的是确定多倍体如何影响脊椎动物的生理过程，以鱼类为实验模型。多倍体的基因组中有多于正常（二倍体）的两条染色体：三倍体有三条，四倍体有四条，等等。多倍体在脊椎动物的进化中扮演着重要的角色，它提供了冗余的基因，这些基因可以在不造成致命的情况下突变。多倍体的结果是细胞核占细胞总体积较大比例的细胞体积增加，导致细胞数量减少，单位体积的细胞和核表面积减少，细胞内扩散距离增加。这些变化可能会对个体动物施加生理限制，从而抵消多倍体的长期（进化）遗传益处。这项研究旨在确定这些限制的本质，从而帮助评估多倍体作为进化驱动因素的更广泛意义。本研究的重点是多倍体如何影响鱼类红细胞动力学和有氧范围。这项研究将以鲑科鱼和斑马鱼两种鱼类进行，前者是相对较大的、易于养殖的鱼类，对水产养殖和渔业管理具有重要意义，后者是一种受欢迎的观水鱼，已成为脊椎动物发育研究中最重要的模式物种之一。五名本科生和四名研究生将在这项资助下接受培训。除了从这项研究中获得的基本知识外，它还将有利于加拿大的水产养殖和渔业管理，因为三倍体被视为创造生殖不育鱼类种群的宝贵工具。了解三倍体的局限性将有助于改善它们的饲养，并确保它们的福利得到适当的考虑。

The objective of this research is to determine how polyploidy affects physiological processes in vertebrates, using fish as experimental models. Polyploids have more than the normal (diploid) two chromosome sets in their genomes: triploids have three, tetraploids have four, etc. Polyploidy has played an important role in vertebrate evolution by providing redundant genes that can mutate without causing lethality. A consequence of polyploidy is increased cell volume in cells for which the nucleus occupies a relatively large proportion of total cell volume, resulting in reduced cell numbers, reduced cellular and nuclear surface area per unit volume, and increased intracellular diffusion distances. These changes likely impose physiological constraints on individual animals that counterbalance the long-term (evolutionary) genetic benefits of polyploidy. This research aims to determine the nature of such constraints, thereby helping to assess the broader significance of polyploidy as a driver of evolution. The focus of this research is on how polyploidy affects erythrocyte dynamics and aerobic scope in fish. The research will be conducted with both salmonids - relatively large, easily cultured fish of importance for aquaculture and fisheries management - and zebrafish - a popular aquarium fish that has become one of the most important model species for research on vertebrate development. Five undergraduate and four graduate students will be trained with funding from this grant. In addition to the basic knowledge gained from this research, it will benefit aquaculture and fisheries management in Canada, as triploidy is seen as a valuable tool for creating reproductively sterile populations of fish. Understanding the limitations of triploids will lead to improvements in their husbandry and will ensure that their welfare is properly considered.