Sorbonne Université, UPEC, CNRS, IRD, INRA, Institute of Ecology and Environmental Sciences of Paris, IEES-Paris, 75005, Paris, France.
Université Paris Cité, CNRS, Institut Jacques Monod, 75013, Paris, France.
Chromosome Res. 2024 Jul 22;32(3):10. doi: 10.1007/s10577-024-09755-x.
The number of chromosomes varies tremendously across species. It is not clear whether having more or fewer chromosomes could be advantageous. The probability of non-disjunction should theoretically decrease with smaller karyotypes, but too long chromosomes should enforce spatial constraint for their segregation during the mitotic anaphase. Here, we propose a new experimental cell system to acquire novel insights into the mechanisms underlying chromosome segregation. We collected the endemic Australian ant Myrmecia croslandi, the only known species with the simplest possible karyotype of a single chromosome in the haploid males (and one pair of chromosomes in the diploid females), since males are typically haploid in hymenopteran insects. Five colonies, each with a queen and a few hundreds of workers, were collected in the Canberra district (Australia), underwent karyotype analysis to confirm the presence of a single pair of chromosomes in worker pupae, and were subsequently maintained in the laboratory in Paris (France). Starting from dissociated male embryos, we successfully conducted primary cell cultures comprised of single-chromosome cells. This could be developed into a unique model that will be of great interest for future genomic and cell biology studies related to mitosis.
染色体的数量在物种间差异极大。拥有更多或更少的染色体是否有利尚不清楚。非整倍体的概率理论上应该随着较小的核型而降低，但过长的染色体在有丝分裂后期分离时应该会对其空间约束施加压力。在这里，我们提出了一种新的实验细胞系统，以深入了解染色体分离的机制。我们收集了澳大利亚特有蚂蚁 Myrmecia croslandi，这是已知的唯一一种在雄性（雌性为二倍体时有一对染色体）中具有最简单的单染色体核型的物种，因为雄性在膜翅目昆虫中通常是单倍体。五个殖民地，每个殖民地都有一个女王和几百个工蚁，在堪培拉地区（澳大利亚）被收集，进行核型分析以确认工蚁蛹中存在一对染色体，随后在法国巴黎的实验室中进行维持。从分离的雄性胚胎开始，我们成功地进行了由单染色体细胞组成的原代细胞培养。这可能发展成为一个独特的模型，对于未来与有丝分裂相关的基因组和细胞生物学研究将非常有意义。
