Our fourth selection for an innovation that changed mammalogy is actually a series of innovations that accumulated over a period of at least 15 years, and opened the way for researchers to be able to karyotype wild mammals under the most challenging fieldwork conditions. By 1950, the basics of chromosomes were understood, but getting accurate chromosome counts was “exceedingly tedious and often inaccurate” (Baker and Hafner 1994:313). The problem for mammals was made more difficult by the high chromosome counts that characterize many species. For example, the human chromosome count was believed to be 48 at this time, rather than the 46 we know today. The old technique was to squash cells on a microscope slide with a coverslip, resulting in poorly spread chromosomes with overlapping sections that did not focus in the same plane under a microscope. The chances of viewing a good (countable) spread were diminished further by the fact that, under normal conditions, there is a limited number of cells in metaphase at any one time (Matthey 1953; Sachs 1953; Hsu 1979).

中文翻译：

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改变哺乳动物学的创新：核型研究的现场技术

我们对改变哺乳动物学的创新的第四次选择实际上是至少在15年内积累的一系列创新，这为研究人员在最具挑战性的野外工作条件下对野生哺乳动物进行核型化开辟了道路。到1950年，人们已经了解了染色体的基本知识，但是获得准确的染色体计数“非常繁琐，而且常常不准确”（Baker和Hafner，1994：313）。哺乳动物的问题由于许多物种的高染色体数而变得更加困难。例如，目前认为人类染色体数为48，而不是我们今天知道的46。过去的技术是用盖玻片将细胞压扁在显微镜载玻片上，导致染色体分布不佳，具有重叠的部分，而这些部分在显微镜下未聚焦在同一平面上。