牛染色体的G带、C带，姐妹单体互换的观察

Observation on the Giemsa G-,C-banding and Sce of Cattle (Bos Taurus) Chromosomes

摘要: 近年来，由于染色体分带、姐妹单体互换等新技术的发展，大大促进了对哺乳动物染色体的研究工作。牛的染色体共30对(2n=60)，除性染色体为亚中央着丝粒外，其余29对常染色体均为端着丝粒，只根据着丝粒的位置，染色体的大小、很难在彼此间加以区别。因此本文报导了牛染色体的G带、C带分析，以有助于识别和鉴定牛的各条染色体，并报道了姐妹单体互换(SCE)的自发频率。

Abstract: Metaphase chromosome specimens were made from leukocyte cultures of a newborn calf according to standard technique.The G-and G-banding petterns were described.These results indicated that the diploid chromosome number of cattle cell is 60.With the exception of the sex chromosome which is submetacentric,all the autosomes appeared to be belocentric.The sister chromatid exchanges were visualized by differential staining with Giemsa.The spontaneous frequencies of SCE in the cells were counted.The mean number of SCE per normal cattle cell is 5.9±1.2.