West J D, Hodson B A, Keighren M A
Department of Obstetrics and Gynaecology, University of Edinburgh, UK.
Dev Growth Differ. 1997 Jun;39(3):305-17. doi: 10.1046/j.1440-169x.1997.t01-2-00006.x.
The spatial distribution of cells in chimaeric tissues, composed of two genotypes, provides insights into the extent of cell mixing during development and growth. However, direct measurement of patch sizes is not usually meaningful because, when the proportion of one genotype is high, a single patch may encompass several adjacent coherent clones of like genotype (clone aggregation). Two previously used methods of comparing patch lengths were evaluated to overcome this problem. The corrected mean patch length (corrected for the predicted effects of random clone aggregation) is a more useful summary statistic than the median patch length of the minor genotype, because its use is not restricted to grossly unbalanced chimaeras, but its validity has been questioned. The two methods gave almost identical numerical summaries of patch sizes in the retinal pigment epithelium of fetal chimaeras, thereby validating the use of the corrected mean patch length for this tissue. The present study also showed that the corrected patch length was unaffected by the presence of cells hemizygous for the TgN(Hbb-b1)83Clo transgene and that the proportion of pigmented cells in a single histological section was representative of the overall composition of the chimaeric fetus.
由两种基因型组成的嵌合组织中细胞的空间分布，为发育和生长过程中细胞混合的程度提供了见解。然而，直接测量斑块大小通常没有意义，因为当一种基因型的比例很高时，单个斑块可能包含几个相邻的相同基因型的连贯克隆（克隆聚集）。为克服这一问题，对之前使用的两种比较斑块长度的方法进行了评估。校正后的平均斑块长度（校正了随机克隆聚集的预测影响）比次要基因型的中值斑块长度更有用，因为它的使用不限于严重不平衡的嵌合体，但其有效性受到了质疑。这两种方法对胎儿嵌合体视网膜色素上皮中斑块大小的数值总结几乎相同，从而验证了校正后的平均斑块长度在该组织中的应用。本研究还表明，校正后的斑块长度不受TgN(Hbb-b1)83Clo转基因半合子细胞存在的影响，并且单个组织学切片中色素细胞的比例代表了嵌合胎儿的整体组成。
