Analysis of replication pattern in soybean chromosomes by indirect immunofluorescence method

An indirect immunofluorescence method detecting the incorporation of BrdU was applied to analyze the DNA replication pattern in soybean chromosomes which are very small among plant species so far examined. Discrete fluorescent images in the distal, interstitial and proximal regions of the chromosome arms were revealed at prometaphase. Time-course analysis indicated that the DNA replication starts at the distal region. The replication patterns are discussed in relation to other chromosomal characteristics such as the location of constitutive heterochromatin and the stainability with the Giemsa.