ヒナバッタ精母細胞染色体におけるクロモアメ分折

Pachytene chromosomes of grasshopper spermatocyes were observed with squashed-Feulgen stain preparations for an analysis of the chromomere pattern in the bivalents. Eleven bivalents were identifiable in well-spread cells, in consequence the measurements of chromosome length and chromomere count of each chromosome were possible. The examination indicated that the number and pattern of chromomeres varied according as the pachytene stage proceeds. The number of chromomeres was much higher in elongated chromosomes and lower in condensed elements. Therefore the chromomere distribution, measured by the average distance between chromomeres, was a farrly good approximation in respective bivalent. Identical pattern of chromomere arrangement was detected only at advanced stage of pachytene since the contraction of chromosomes and chromomere fusion brought better visualization of the number and disposition.