Cherniak Christopher, Rodriguez-Esteban Raul
Committee for Philosophy and the Sciences, Department of Philosophy, University of Maryland, College Park, MD 20742, USA.
Mol Cytogenet. 2013 Dec 20;6(1):61. doi: 10.1186/1755-8166-6-61.
Chromosomes have territories, or preferred locales, in the cell nucleus. When these sites are taken into account, some large-scale structure of the human genome emerges.
The synoptic picture is that genes highly expressed in particular topologically compact tissues are not randomly distributed on the genome. Rather, such tissue-specific genes tend to map somatotopically onto the complete chromosome set. They seem to form a "genome homunculus": a multi-dimensional, genome-wide body representation extending across chromosome territories of the entire spermcell nucleus. The antero-posterior axis of the body significantly corresponds to the head-tail axis of the nucleus, and the dorso-ventral body axis to the central-peripheral nucleus axis.
This large-scale genomic structure includes thousands of genes. One rationale for a homuncular genome structure would be to minimize connection costs in genetic networks. Somatotopic maps in cerebral cortex have been reported for over a century.
染色体在细胞核中有特定区域,即偏好定位。考虑这些位点时,人类基因组的一些大规模结构就会显现出来。
总体情况是,在特定拓扑紧密组织中高表达的基因并非随机分布在基因组上。相反,这类组织特异性基因倾向于以躯体定位的方式映射到完整的染色体组上。它们似乎形成了一个“基因组小人”:一种跨整个精子细胞核染色体区域的多维、全基因组范围的身体表征。身体的前后轴与细胞核的头尾轴显著对应,背腹身体轴与细胞核的中央 - 外周轴对应。
这种大规模基因组结构包含数千个基因。基因组小人结构的一个基本原理可能是使遗传网络中的连接成本最小化。大脑皮层中的躯体定位图已有一个多世纪的报道。