Mezger-Freed L
Chromosoma. 1977 Jun 30;62(1):1-15. doi: 10.1007/BF00328437.
ICR 2A, a haploid cell line derived from Rana pipiens embryos, has remained haploid in number of chromosones and their relative lengths and centromere positions for 500 cell generations. After this time, two new haryotypes appeared; relative length measurements indicate that the first has a translocation from chromosome 4 to 6, the second translocations from 3 and 4 to 6 and 7. The single exchange karyotype is not a precursor for the double exchange according to a statistical analysis. The double exchange karyotype characterized 90% of some cultures although a selective advantage could not be demonstrated for these cells. The observations suggest that a non-clonal or multicellular origin may account for these karyotypic variants.
ICR 2A是一种源自豹蛙胚胎的单倍体细胞系，在500个细胞世代中，其染色体数目、相对长度和着丝粒位置一直保持单倍体状态。在此之后，出现了两种新的核型；相对长度测量表明，第一种是4号染色体到6号染色体的易位，第二种是3号和4号染色体到6号和7号染色体的易位。根据统计分析，单交换核型不是双交换核型的前体。双交换核型在某些培养物中占90%，尽管这些细胞没有显示出选择优势。这些观察结果表明，非克隆或多细胞起源可能是这些核型变异的原因。
