An account is given of my development of techniques to obtain well-spread Giemsa-stained banded chromosome preparations. Apparent G-banding could be obtained following very slight trypsin treatment of freshly prepared slides, but this banding was very fine (close-grained) and possibly not a reflection of chromosome structure. However, treatment of developing embryos in vitro with 5-fluorouridine produced a similar chromomere banding, which is therefore regarded as genuine. Steady accumulation of Helophorus Fabricius, 1775 karyotypes has resulted in the production of an Atlas covering 62 of the 170 species known to occur in the Palaearctic. Chromosome polymorphisms involving pericentric inversions and addition of extra C-banding regions have been found, as well as small B-chromosomes in a few species. In general, karyotypes have proved very useful in establishing the limits of individual species. Parthenogenesis involving triploidy has been found in two species. Karyotypes of experimentally produced hybrids have revealed irregularities in chromosome condensation.

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更新的 Helophorus 染色体图谱

 描述了我开发的技术以获得良好铺展的吉姆萨染色带状染色体制剂。对新鲜制备的载玻片进行非常轻微的胰蛋白酶处理后，可以获得明显的 G 带，但这种带非常细（紧密），可能不是染色体结构的反映。然而，用 5-氟尿苷在体外处理发育中的胚胎产生了类似的染色体条带，因此被认为是真实的。Helophorus Fabricius 1775 核型的稳定积累已经产生了一个图集，涵盖了古北界已知的 170 个物种中的 62 个物种。已发现涉及中心周倒位和添加额外 C 带区域的染色体多态性，以及少数物种中的小 B 染色体。一般来说，核型已被证明对于确定个体物种的限制非常有用。在两个物种中发现了涉及三倍体的孤雌生殖。实验产生的杂交体的核型揭示了染色体凝聚的不规则性。